Been running this patch for just over a month now, and suddenly:
Pid: 0, comm: swapper
EIP: 0060:[<e09a229a>] CPU: 0
EIP is at regnext+0x20/0x36 [ipt_layer7]
EFLAGS: 00000206 Not tainted (2.6.16.27xs20060817dell #2)
EAX: 00000003 EBX: 00000000 ECX: dfc89b8d EDX: 00000003
ESI: dfc89b8d EDI: dfc89a70 EBP: c03bb76c DS: 007b ES: 007b
CR0: 8005003b CR2: b7fce000 CR3: 1ce84000 CR4: 000006d0
[<c0103a47>] show_trace+0x20/0x22
[<c0101101>] show_regs+0x166/0x18d
[<c013bd94>] softlockup_tick+0x7d/0x86
[<c01272c2>] do_timer+0x45/0xe8
[<c01066d8>] timer_interrupt+0x83/0xaa
[<c013bf37>] handle_IRQ_event+0x3e/0x73
[<c013bff3>] __do_IRQ+0x87/0xec
[<c01051dc>] do_IRQ+0x1c/0x28
[<c010361e>] common_interrupt+0x1a/0x20
[<e09a1e61>] regmatch+0x23/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a1ea8>] regmatch+0x6a/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a1ee7>] regmatch+0xa9/0x2bb [ipt_layer7]
[<e09a20c5>] regmatch+0x287/0x2bb [ipt_layer7]
[<e09a1ee7>] regmatch+0xa9/0x2bb [ipt_layer7]
[<e09a1e22>] regtry+0x4c/0x68 [ipt_layer7]
[<e09a1dcf>] regexec+0x199/0x1a0 [ipt_layer7]
[<e09a287f>] match+0x19b/0x2ec [ipt_layer7]
[<e080d1e5>] ipt_do_table+0x1bb/0x325 [ip_tables]
[<e0812036>] ipt_route_hook+0x36/0x38 [iptable_mangle]
[<c0283f9a>] nf_iterate+0x5f/0x83
[<c0284021>] nf_hook_slow+0x63/0x10d
[<c02d58e7>] br_nf_pre_routing+0x54c/0x55a
[<c0283f9a>] nf_iterate+0x5f/0x83
[<c0284021>] nf_hook_slow+0x63/0x10d
[<c02d1203>] br_handle_frame+0x1c0/0x22d
[<c026e6a6>] netif_receive_skb+0x146/0x32a
[<c022223d>] tg3_rx+0x2da/0x40e
[<c02223cf>] tg3_poll+0x5e/0x15a
[<c026ea59>] net_rx_action+0xc3/0x116
[<c0122eeb>] __do_softirq+0x6f/0xde
[<c0122f90>] do_softirq+0x36/0x38
[<c0123049>] irq_exit+0x38/0x3a
[<c01051e1>] do_IRQ+0x21/0x28
[<c010361e>] common_interrupt+0x1a/0x20
[<c0100ddc>] cpu_idle+0x8f/0x91
[<c01002c9>] rest_init+0x31/0x33
[<c03bc8c5>] start_kernel+0x15d/0x174
[<c0100210>] 0xc0100210
Seems this bug is still there. I am beginning to think it may be an
infinite recursion (or excessively long processing) inside reg_match.
Could explain why Andy managed to trigger it under a uniprocessor box
(although I have a number of uniprocessor boxes running for over a year
without ever experiencing it!).
What is the current status of the userspace l7? Is the performance OK
for 1000pps + networks? Stability? SMP safe?
Thanks,
Justin
Matthew Strait wrote:
>> It seems the current fixes _do not_ catch the SMP lockup...
>
> Attached is an l7-filter patch which is as paranoid (and wasteful) as I
> know how to be about locking. It puts a spin_lock_bh around the entire
> match() function. Please test.
>
> -Matthew
>
>
> ------------------------------------------------------------------------
>
> --- linux-2.6.19.1-stock/include/linux/netfilter_ipv4/ip_conntrack.h 2006-12-11 13:32:53.000000000 -0600
> +++ linux-2.6.19.1-layer7/include/linux/netfilter_ipv4/ip_conntrack.h 2006-12-13 00:13:08.000000000 -0600
> @@ -127,6 +127,15 @@ struct ip_conntrack
> /* Traversed often, so hopefully in different cacheline to top */
> /* These are my tuples; original and reply */
> struct ip_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
> +
> +#if defined(CONFIG_IP_NF_MATCH_LAYER7) || defined(CONFIG_IP_NF_MATCH_LAYER7_MODULE)
> + struct {
> + char * app_proto; /* e.g. "http". NULL before decision. "unknown" after decision if no match */
> + char * app_data; /* application layer data so far. NULL after match decision */
> + unsigned int app_data_len;
> + } layer7;
> +#endif
> +
> };
>
> struct ip_conntrack_expect
> --- linux-2.6.19.1-stock/include/linux/netfilter_ipv4/ipt_layer7.h 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/include/linux/netfilter_ipv4/ipt_layer7.h 2006-12-13 00:13:08.000000000 -0600
> @@ -0,0 +1,26 @@
> +/*
> + By Matthew Strait <quadong@...>, Dec 2003.
> + http://l7-filter.sf.net
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version
> + 2 of the License, or (at your option) any later version.
> + http://www.gnu.org/licenses/gpl.txt
> +*/
> +
> +#ifndef _IPT_LAYER7_H
> +#define _IPT_LAYER7_H
> +
> +#define MAX_PATTERN_LEN 8192
> +#define MAX_PROTOCOL_LEN 256
> +
> +typedef char *(*proc_ipt_search) (char *, char, char *);
> +
> +struct ipt_layer7_info {
> + char protocol[MAX_PROTOCOL_LEN];
> + char invert:1;
> + char pattern[MAX_PATTERN_LEN];
> +};
> +
> +#endif /* _IPT_LAYER7_H */
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/Kconfig 2006-12-11 13:32:53.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/Kconfig 2006-12-13 00:13:08.000000000 -0600
> @@ -248,6 +248,24 @@ config IP_NF_MATCH_IPRANGE
>
> To compile it as a module, choose M here. If unsure, say N.
>
> +config IP_NF_MATCH_LAYER7
> + tristate "Layer 7 match support (EXPERIMENTAL)"
> + depends on IP_NF_IPTABLES && IP_NF_CT_ACCT && IP_NF_CONNTRACK && EXPERIMENTAL
> + help
> + Say Y if you want to be able to classify connections (and their
> + packets) based on regular expression matching of their application
> + layer data. This is one way to classify applications such as
> + peer-to-peer filesharing systems that do not always use the same
> + port.
> +
> + To compile it as a module, choose M here. If unsure, say N.
> +
> +config IP_NF_MATCH_LAYER7_DEBUG
> + bool "Layer 7 debugging output"
> + depends on IP_NF_MATCH_LAYER7
> + help
> + Say Y to get lots of debugging output.
> +
> config IP_NF_MATCH_TOS
> tristate "TOS match support"
> depends on IP_NF_IPTABLES
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/Makefile 2006-12-11 13:32:53.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/Makefile 2006-12-13 00:13:08.000000000 -0600
> @@ -63,6 +63,8 @@ obj-$(CONFIG_IP_NF_MATCH_AH) += ipt_ah.o
> obj-$(CONFIG_IP_NF_MATCH_TTL) += ipt_ttl.o
> obj-$(CONFIG_IP_NF_MATCH_ADDRTYPE) += ipt_addrtype.o
>
> +obj-$(CONFIG_IP_NF_MATCH_LAYER7) += ipt_layer7.o
> +
> # targets
> obj-$(CONFIG_IP_NF_TARGET_REJECT) += ipt_REJECT.o
> obj-$(CONFIG_IP_NF_TARGET_TOS) += ipt_TOS.o
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/ip_conntrack_core.c 2006-12-11 13:32:53.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/ip_conntrack_core.c 2006-12-13 00:13:08.000000000 -0600
> @@ -337,6 +337,13 @@ destroy_conntrack(struct nf_conntrack *n
> * too. */
> ip_ct_remove_expectations(ct);
>
> + #if defined(CONFIG_IP_NF_MATCH_LAYER7) || defined(CONFIG_IP_NF_MATCH_LAYER7_MODULE)
> + if(ct->layer7.app_proto)
> + kfree(ct->layer7.app_proto);
> + if(ct->layer7.app_data)
> + kfree(ct->layer7.app_data);
> + #endif
> +
> /* We overload first tuple to link into unconfirmed list. */
> if (!is_confirmed(ct)) {
> BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/ip_conntrack_standalone.c 2006-12-11 13:32:53.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/ip_conntrack_standalone.c 2006-12-13 00:13:08.000000000 -0600
> @@ -192,6 +192,12 @@ static int ct_seq_show(struct seq_file *
> return -ENOSPC;
> #endif
>
> +#if defined(CONFIG_IP_NF_MATCH_LAYER7) || defined(CONFIG_IP_NF_MATCH_LAYER7_MODULE)
> + if(conntrack->layer7.app_proto)
> + if (seq_printf(s, "l7proto=%s ",conntrack->layer7.app_proto))
> + return 1;
> +#endif
> +
> if (seq_printf(s, "use=%u\n", atomic_read(&conntrack->ct_general.use)))
> return -ENOSPC;
>
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/ipt_layer7.c 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/ipt_layer7.c 2007-01-03 22:17:45.000000000 -0600
> @@ -0,0 +1,555 @@
> +/*
> + Kernel module to match application layer (OSI layer 7) data in connections.
> +
> + http://l7-filter.sf.net
> +
> + By Matthew Strait and Ethan Sommer, 2003-2006.
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version
> + 2 of the License, or (at your option) any later version.
> + http://www.gnu.org/licenses/gpl.txt
> +
> + Based on ipt_string.c (C) 2000 Emmanuel Roger <winfield@...>
> + and cls_layer7.c (C) 2003 Matthew Strait, Ethan Sommer, Justin Levandoski
> +*/
> +
> +#include <linux/module.h>
> +#include <linux/skbuff.h>
> +#include <linux/netfilter_ipv4/ip_conntrack.h>
> +#include <linux/proc_fs.h>
> +#include <linux/ctype.h>
> +#include <net/ip.h>
> +#include <net/tcp.h>
> +#include <linux/spinlock.h>
> +
> +#include "regexp/regexp.c"
> +
> +#include <linux/netfilter_ipv4/ipt_layer7.h>
> +#include <linux/netfilter_ipv4/ip_tables.h>
> +
> +MODULE_AUTHOR("Matthew Strait <quadong@...>, Ethan Sommer <sommere@...>");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("iptables application layer match module");
> +MODULE_VERSION("2.0");
> +
> +static int maxdatalen = 2048; // this is the default
> +module_param(maxdatalen, int, 0444);
> +MODULE_PARM_DESC(maxdatalen, "maximum bytes of data looked at by l7-filter");
> +
> +#ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
> + #define DPRINTK(format,args...) printk(format,##args)
> +#else
> + #define DPRINTK(format,args...)
> +#endif
> +
> +#define TOTAL_PACKETS master_conntrack->counters[IP_CT_DIR_ORIGINAL].packets + \
> + master_conntrack->counters[IP_CT_DIR_REPLY].packets
> +
> +/* Number of packets whose data we look at.
> +This can be modified through /proc/net/layer7_numpackets */
> +static int num_packets = 10;
> +
> +static struct pattern_cache {
> + char * regex_string;
> + regexp * pattern;
> + struct pattern_cache * next;
> +} * first_pattern_cache = NULL;
> +
> +DEFINE_SPINLOCK(l7_lock);
> +
> +#ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
> +/* Converts an unfriendly string into a friendly one by
> +replacing unprintables with periods and all whitespace with " ". */
> +static char * friendly_print(unsigned char * s)
> +{
> + char * f = kmalloc(strlen(s) + 1, GFP_ATOMIC);
> + int i;
> +
> + if(!f) {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in friendly_print, bailing.\n");
> + return NULL;
> + }
> +
> + for(i = 0; i < strlen(s); i++){
> + if(isprint(s[i]) && s[i] < 128) f[i] = s[i];
> + else if(isspace(s[i])) f[i] = ' ';
> + else f[i] = '.';
> + }
> + f[i] = '\0';
> + return f;
> +}
> +
> +static char dec2hex(int i)
> +{
> + switch (i) {
> + case 0 ... 9:
> + return (char)(i + '0');
> + break;
> + case 10 ... 15:
> + return (char)(i - 10 + 'a');
> + break;
> + default:
> + if (net_ratelimit())
> + printk("Problem in dec2hex\n");
> + return '\0';
> + }
> +}
> +
> +static char * hex_print(unsigned char * s)
> +{
> + char * g = kmalloc(strlen(s)*3 + 1, GFP_ATOMIC);
> + int i;
> +
> + if(!g) {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in hex_print, bailing.\n");
> + return NULL;
> + }
> +
> + for(i = 0; i < strlen(s); i++) {
> + g[i*3 ] = dec2hex(s[i]/16);
> + g[i*3 + 1] = dec2hex(s[i]%16);
> + g[i*3 + 2] = ' ';
> + }
> + g[i*3] = '\0';
> +
> + return g;
> +}
> +#endif // DEBUG
> +
> +/* Use instead of regcomp. As we expect to be seeing the same regexps over and
> +over again, it make sense to cache the results. */
> +static regexp * compile_and_cache(char * regex_string, char * protocol)
> +{
> + struct pattern_cache * node = first_pattern_cache;
> + struct pattern_cache * last_pattern_cache = first_pattern_cache;
> + struct pattern_cache * tmp;
> + unsigned int len;
> +
> + while (node != NULL) {
> + if (!strcmp(node->regex_string, regex_string))
> + return node->pattern;
> +
> + last_pattern_cache = node;/* points at the last non-NULL node */
> + node = node->next;
> + }
> +
> + /* If we reach the end of the list, then we have not yet cached
> + the pattern for this regex. Let's do that now.
> + Be paranoid about running out of memory to avoid list corruption. */
> + tmp = kmalloc(sizeof(struct pattern_cache), GFP_ATOMIC);
> +
> + if(!tmp) {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in compile_and_cache, bailing.\n");
> + return NULL;
> + }
> +
> + tmp->regex_string = kmalloc(strlen(regex_string) + 1, GFP_ATOMIC);
> + tmp->pattern = kmalloc(sizeof(struct regexp), GFP_ATOMIC);
> + tmp->next = NULL;
> +
> + if(!tmp->regex_string || !tmp->pattern) {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in compile_and_cache, bailing.\n");
> + kfree(tmp->regex_string);
> + kfree(tmp->pattern);
> + kfree(tmp);
> + return NULL;
> + }
> +
> + /* Ok. The new node is all ready now. */
> + node = tmp;
> +
> + if(first_pattern_cache == NULL) /* list is empty */
> + first_pattern_cache = node; /* make node the beginning */
> + else
> + last_pattern_cache->next = node; /* attach node to the end */
> +
> + /* copy the string and compile the regex */
> + len = strlen(regex_string);
> + DPRINTK("About to compile this: \"%s\"\n", regex_string);
> + node->pattern = regcomp(regex_string, &len);
> + if ( !node->pattern ) {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: Error compiling regexp \"%s\" (%s)\n", regex_string, protocol);
> + /* pattern is now cached as NULL, so we won't try again. */
> + }
> +
> + strcpy(node->regex_string, regex_string);
> + return node->pattern;
> +}
> +
> +static int can_handle(const struct sk_buff *skb)
> +{
> + if(!skb->nh.iph) /* not IP */
> + return 0;
> + if(skb->nh.iph->protocol != IPPROTO_TCP &&
> + skb->nh.iph->protocol != IPPROTO_UDP &&
> + skb->nh.iph->protocol != IPPROTO_ICMP)
> + return 0;
> + return 1;
> +}
> +
> +/* Returns offset the into the skb->data that the application data starts */
> +static int app_data_offset(const struct sk_buff *skb)
> +{
> + /* In case we are ported somewhere (ebtables?) where skb->nh.iph
> + isn't set, this can be gotten from 4*(skb->data[0] & 0x0f) as well. */
> + int ip_hl = 4*skb->nh.iph->ihl;
> +
> + if( skb->nh.iph->protocol == IPPROTO_TCP ) {
> + /* 12 == offset into TCP header for the header length field.
> + Can't get this with skb->h.th->doff because the tcphdr
> + struct doesn't get set when routing (this is confirmed to be
> + true in Netfilter as well as QoS.) */
> + int tcp_hl = 4*(skb->data[ip_hl + 12] >> 4);
> +
> + return ip_hl + tcp_hl;
> + } else if( skb->nh.iph->protocol == IPPROTO_UDP ) {
> + return ip_hl + 8; /* UDP header is always 8 bytes */
> + } else if( skb->nh.iph->protocol == IPPROTO_ICMP ) {
> + return ip_hl + 8; /* ICMP header is 8 bytes */
> + } else {
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: tried to handle unknown protocol!\n");
> + return ip_hl + 8; /* something reasonable */
> + }
> +}
> +
> +/* handles whether there's a match when we aren't appending data anymore */
> +static int match_no_append(struct ip_conntrack * conntrack, struct ip_conntrack * master_conntrack,
> + enum ip_conntrack_info ctinfo, enum ip_conntrack_info master_ctinfo,
> + struct ipt_layer7_info * info)
> +{
> + /* If we're in here, throw the app data away */
> + if(master_conntrack->layer7.app_data != NULL) {
> +
> + #ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
> + if(!master_conntrack->layer7.app_proto) {
> + char * f = friendly_print(master_conntrack->layer7.app_data);
> + char * g = hex_print(master_conntrack->layer7.app_data);
> + DPRINTK("\nl7-filter gave up after %d bytes (%d packets):\n%s\n",
> + strlen(f), TOTAL_PACKETS, f);
> + kfree(f);
> + DPRINTK("In hex: %s\n", g);
> + kfree(g);
> + }
> + #endif
> +
> + kfree(master_conntrack->layer7.app_data);
> + master_conntrack->layer7.app_data = NULL; /* don't free again */
> + }
> +
> + if(master_conntrack->layer7.app_proto){
> + /* Here child connections set their .app_proto (for /proc/net/ip_conntrack) */
> + if(!conntrack->layer7.app_proto) {
> + conntrack->layer7.app_proto = kmalloc(strlen(master_conntrack->layer7.app_proto)+1, GFP_ATOMIC);
> + if(!conntrack->layer7.app_proto){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in match_no_append, bailing.\n");
> + return 1;
> + }
> + strcpy(conntrack->layer7.app_proto, master_conntrack->layer7.app_proto);
> + }
> +
> + return (!strcmp(master_conntrack->layer7.app_proto, info->protocol));
> + }
> + else {
> + /* If not classified, set to "unknown" to distinguish from
> + connections that are still being tested. */
> + master_conntrack->layer7.app_proto = kmalloc(strlen("unknown")+1, GFP_ATOMIC);
> + if(!master_conntrack->layer7.app_proto){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in match_no_append, bailing.\n");
> + return 1;
> + }
> + strcpy(master_conntrack->layer7.app_proto, "unknown");
> + return 0;
> + }
> +}
> +
> +/* add the new app data to the conntrack. Return number of bytes added. */
> +static int add_data(struct ip_conntrack * master_conntrack,
> + char * app_data, int appdatalen)
> +{
> + int length = 0, i;
> + int oldlength = master_conntrack->layer7.app_data_len;
> +
> + // This is a fix for a race condition by Deti Fliegl. However, I'm not
> + // clear on whether the race condition exists or whether this really
> + // fixes it. I might just be being dense... Anyway, if it's not really
> + // a fix, all it does is waste a very small amount of time.
> + if(!master_conntrack->layer7.app_data) return 0;
> +
> + /* Strip nulls. Make everything lower case (our regex lib doesn't
> + do case insensitivity). Add it to the end of the current data. */
> + for(i = 0; i < maxdatalen-oldlength-1 &&
> + i < appdatalen; i++) {
> + if(app_data[i] != '\0') {
> + master_conntrack->layer7.app_data[length+oldlength] =
> + /* the kernel version of tolower mungs 'upper ascii' */
> + isascii(app_data[i])? tolower(app_data[i]) : app_data[i];
> + length++;
> + }
> + }
> +
> + master_conntrack->layer7.app_data[length+oldlength] = '\0';
> + master_conntrack->layer7.app_data_len = length + oldlength;
> +
> + return length;
> +}
> +
> +/* Returns true on match and false otherwise. */
> +static int match(const struct sk_buff *skbin,
> + const struct net_device *in, const struct net_device *out,
> + const struct xt_match *match, const void *matchinfo,
> + int offset, unsigned int protoff, int *hotdrop)
> +{
> + /* sidestep const without getting a compiler warning... */
> + struct sk_buff * skb = (struct sk_buff *)skbin;
> +
> + struct ipt_layer7_info * info = (struct ipt_layer7_info *)matchinfo;
> + enum ip_conntrack_info master_ctinfo, ctinfo;
> + struct ip_conntrack *master_conntrack, *conntrack;
> + unsigned char * app_data;
> + unsigned int pattern_result, appdatalen;
> + regexp * comppattern;
> +
> + /* TEST VERSION - lock the entire match function. */
> + spin_lock_bh(&l7_lock);
> +
> + if(!can_handle(skb)){
> + DPRINTK("layer7: This is some protocol I can't handle.\n");
> + spin_unlock_bh(&l7_lock);
> + return info->invert;
> + }
> +
> + /* Treat parent & all its children together as one connection, except
> + for the purpose of setting conntrack->layer7.app_proto in the actual
> + connection. This makes /proc/net/ip_conntrack more satisfying. */
> + if(!(conntrack = ip_conntrack_get((struct sk_buff *)skb, &ctinfo)) ||
> + !(master_conntrack = ip_conntrack_get((struct sk_buff *)skb, &master_ctinfo))) {
> + spin_unlock_bh(&l7_lock);
> + return info->invert;
> + }
> +
> + /* Try to get a master conntrack (and its master etc) for FTP, etc. */
> + while (master_ct(master_conntrack) != NULL)
> + master_conntrack = master_ct(master_conntrack);
> +
> + /* if we've classified it or seen too many packets */
> + if(TOTAL_PACKETS > num_packets ||
> + master_conntrack->layer7.app_proto) {
> +
> + pattern_result = match_no_append(conntrack, master_conntrack, ctinfo, master_ctinfo, info);
> +
> + /* skb->cb[0] == seen. Don't do things twice if there are multiple l7
> + rules. I'm not sure that using cb for this purpose is correct, even though
> + it says "put your private variables there". But it doesn't look like it
> + is being used for anything else in the skbs that make it here. */
> + skb->cb[0] = 1; /* marking it seen here is probably irrelevant, but consistant */
> +
> + spin_unlock_bh(&l7_lock);
> + return (pattern_result ^ info->invert);
> + }
> +
> + if(skb_is_nonlinear(skb)){
> + if(skb_linearize(skb) != 0){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: failed to linearize packet, bailing.\n");
> + spin_unlock_bh(&l7_lock);
> + return info->invert;
> + }
> + }
> +
> + /* now that the skb is linearized, it's safe to set these. */
> + app_data = skb->data + app_data_offset(skb);
> + appdatalen = skb->tail - app_data;
> +
> + /* the return value gets checked later, when we're ready to use it */
> + comppattern = compile_and_cache(info->pattern, info->protocol);
> +
> + /* On the first packet of a connection, allocate space for app data */
> + if(TOTAL_PACKETS == 1 && !skb->cb[0] && !master_conntrack->layer7.app_data) {
> + master_conntrack->layer7.app_data = kmalloc(maxdatalen, GFP_ATOMIC);
> + if(!master_conntrack->layer7.app_data){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in match, bailing.\n");
> + spin_unlock_bh(&l7_lock);
> + return info->invert;
> + }
> +
> + master_conntrack->layer7.app_data[0] = '\0';
> + }
> +
> + /* Can be here, but unallocated, if numpackets is increased near
> + the beginning of a connection */
> + if(master_conntrack->layer7.app_data == NULL){
> + spin_unlock_bh(&l7_lock);
> + return (info->invert); /* unmatched */
> + }
> +
> + if(!skb->cb[0]){
> + int newbytes;
> + newbytes = add_data(master_conntrack, app_data, appdatalen);
> +
> + if(newbytes == 0) { /* didn't add any data */
> + skb->cb[0] = 1;
> + /* Didn't match before, not going to match now */
> + spin_unlock_bh(&l7_lock);
> + return info->invert;
> + }
> + }
> +
> + /* If looking for "unknown", then never match. "Unknown" means that
> + we've given up; we're still trying with these packets. */
> + if(!strcmp(info->protocol, "unknown")) {
> + pattern_result = 0;
> + /* If looking for "unset", then always match. "Unset" means that we
> + haven't yet classified the connection. */
> + } else if(!strcmp(info->protocol, "unset")) {
> + pattern_result = 2;
> + DPRINTK("layer7: matched unset: not yet classified (%d/%d packets)\n", TOTAL_PACKETS, num_packets);
> + /* If the regexp failed to compile, don't bother running it */
> + } else if(comppattern && regexec(comppattern, master_conntrack->layer7.app_data)) {
> + DPRINTK("layer7: matched %s\n", info->protocol);
> + pattern_result = 1;
> + } else pattern_result = 0;
> +
> + if(pattern_result == 1) {
> + master_conntrack->layer7.app_proto = kmalloc(strlen(info->protocol)+1, GFP_ATOMIC);
> + if(!master_conntrack->layer7.app_proto){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory in match, bailing.\n");
> + spin_unlock_bh(&l7_lock);
> + return (pattern_result ^ info->invert);
> + }
> + strcpy(master_conntrack->layer7.app_proto, info->protocol);
> + } else if(pattern_result > 1) { /* cleanup from "unset" */
> + pattern_result = 1;
> + }
> +
> + /* mark the packet seen */
> + skb->cb[0] = 1;
> +
> + spin_unlock_bh(&l7_lock);
> + return (pattern_result ^ info->invert);
> +}
> +
> +static struct ipt_match layer7_match = {
> + .name = "layer7",
> + .match = &match,
> + .matchsize = sizeof(struct ipt_layer7_info),
> + .me = THIS_MODULE
> +};
> +
> +/* taken from drivers/video/modedb.c */
> +static int my_atoi(const char *s)
> +{
> + int val = 0;
> +
> + for (;; s++) {
> + switch (*s) {
> + case '0'...'9':
> + val = 10*val+(*s-'0');
> + break;
> + default:
> + return val;
> + }
> + }
> +}
> +
> +/* write out num_packets to userland. */
> +static int layer7_read_proc(char* page, char ** start, off_t off, int count,
> + int* eof, void * data)
> +{
> + if(num_packets > 99 && net_ratelimit())
> + printk(KERN_ERR "layer7: NOT REACHED. num_packets too big\n");
> +
> + page[0] = num_packets/10 + '0';
> + page[1] = num_packets%10 + '0';
> + page[2] = '\n';
> + page[3] = '\0';
> +
> + *eof=1;
> +
> + return 3;
> +}
> +
> +/* Read in num_packets from userland */
> +static int layer7_write_proc(struct file* file, const char* buffer,
> + unsigned long count, void *data)
> +{
> + char * foo = kmalloc(count, GFP_ATOMIC);
> +
> + if(!foo){
> + if (net_ratelimit())
> + printk(KERN_ERR "layer7: out of memory, bailing. num_packets unchanged.\n");
> + return count;
> + }
> +
> + if(copy_from_user(foo, buffer, count)) {
> + return -EFAULT;
> + }
> +
> +
> + num_packets = my_atoi(foo);
> + kfree (foo);
> +
> + /* This has an arbitrary limit to make the math easier. I'm lazy.
> + But anyway, 99 is a LOT! If you want more, you're doing it wrong! */
> + if(num_packets > 99) {
> + printk(KERN_WARNING "layer7: num_packets can't be > 99.\n");
> + num_packets = 99;
> + } else if(num_packets < 1) {
> + printk(KERN_WARNING "layer7: num_packets can't be < 1.\n");
> + num_packets = 1;
> + }
> +
> + return count;
> +}
> +
> +/* register the proc file */
> +static void layer7_init_proc(void)
> +{
> + struct proc_dir_entry* entry;
> + entry = create_proc_entry("layer7_numpackets", 0644, proc_net);
> + entry->read_proc = layer7_read_proc;
> + entry->write_proc = layer7_write_proc;
> +}
> +
> +static void layer7_cleanup_proc(void)
> +{
> + remove_proc_entry("layer7_numpackets", proc_net);
> +}
> +
> +static int __init ipt_layer7_init(void)
> +{
> + need_conntrack();
> +
> + layer7_init_proc();
> + if(maxdatalen < 1) {
> + printk(KERN_WARNING "layer7: maxdatalen can't be < 1, using 1\n");
> + maxdatalen = 1;
> + }
> + /* This is not a hard limit. It's just here to prevent people from
> + bringing their slow machines to a grinding halt. */
> + else if(maxdatalen > 65536) {
> + printk(KERN_WARNING "layer7: maxdatalen can't be > 65536, using 65536\n");
> + maxdatalen = 65536;
> + }
> + return ipt_register_match(&layer7_match);
> +}
> +
> +static void __exit ipt_layer7_fini(void)
> +{
> + layer7_cleanup_proc();
> + ipt_unregister_match(&layer7_match);
> +}
> +
> +module_init(ipt_layer7_init);
> +module_exit(ipt_layer7_fini);
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/regexp/regexp.c 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/regexp/regexp.c 2006-12-13 00:13:08.000000000 -0600
> @@ -0,0 +1,1197 @@
> +/*
> + * regcomp and regexec -- regsub and regerror are elsewhere
> + * @(#)regexp.c 1.3 of 18 April 87
> + *
> + * Copyright (c) 1986 by University of Toronto.
> + * Written by Henry Spencer. Not derived from licensed software.
> + *
> + * Permission is granted to anyone to use this software for any
> + * purpose on any computer system, and to redistribute it freely,
> + * subject to the following restrictions:
> + *
> + * 1. The author is not responsible for the consequences of use of
> + * this software, no matter how awful, even if they arise
> + * from defects in it.
> + *
> + * 2. The origin of this software must not be misrepresented, either
> + * by explicit claim or by omission.
> + *
> + * 3. Altered versions must be plainly marked as such, and must not
> + * be misrepresented as being the original software.
> + *
> + * Beware that some of this code is subtly aware of the way operator
> + * precedence is structured in regular expressions. Serious changes in
> + * regular-expression syntax might require a total rethink.
> + *
> + * This code was modified by Ethan Sommer to work within the kernel
> + * (it now uses kmalloc etc..)
> + *
> + * Modified slightly by Matthew Strait to use more modern C.
> + */
> +
> +#include "regexp.h"
> +#include "regmagic.h"
> +
> +/* added by ethan and matt. Lets it work in both kernel and user space.
> +(So iptables can use it, for instance.) Yea, it goes both ways... */
> +#if __KERNEL__
> + #define malloc(foo) kmalloc(foo,GFP_ATOMIC)
> +#else
> + #define printk(format,args...) printf(format,##args)
> +#endif
> +
> +void regerror(char * s)
> +{
> + printk("<3>Regexp: %s\n", s);
> + /* NOTREACHED */
> +}
> +
> +/*
> + * The "internal use only" fields in regexp.h are present to pass info from
> + * compile to execute that permits the execute phase to run lots faster on
> + * simple cases. They are:
> + *
> + * regstart char that must begin a match; '\0' if none obvious
> + * reganch is the match anchored (at beginning-of-line only)?
> + * regmust string (pointer into program) that match must include, or NULL
> + * regmlen length of regmust string
> + *
> + * Regstart and reganch permit very fast decisions on suitable starting points
> + * for a match, cutting down the work a lot. Regmust permits fast rejection
> + * of lines that cannot possibly match. The regmust tests are costly enough
> + * that regcomp() supplies a regmust only if the r.e. contains something
> + * potentially expensive (at present, the only such thing detected is * or +
> + * at the start of the r.e., which can involve a lot of backup). Regmlen is
> + * supplied because the test in regexec() needs it and regcomp() is computing
> + * it anyway.
> + */
> +
> +/*
> + * Structure for regexp "program". This is essentially a linear encoding
> + * of a nondeterministic finite-state machine (aka syntax charts or
> + * "railroad normal form" in parsing technology). Each node is an opcode
> + * plus a "next" pointer, possibly plus an operand. "Next" pointers of
> + * all nodes except BRANCH implement concatenation; a "next" pointer with
> + * a BRANCH on both ends of it is connecting two alternatives. (Here we
> + * have one of the subtle syntax dependencies: an individual BRANCH (as
> + * opposed to a collection of them) is never concatenated with anything
> + * because of operator precedence.) The operand of some types of node is
> + * a literal string; for others, it is a node leading into a sub-FSM. In
> + * particular, the operand of a BRANCH node is the first node of the branch.
> + * (NB this is *not* a tree structure: the tail of the branch connects
> + * to the thing following the set of BRANCHes.) The opcodes are:
> + */
> +
> +/* definition number opnd? meaning */
> +#define END 0 /* no End of program. */
> +#define BOL 1 /* no Match "" at beginning of line. */
> +#define EOL 2 /* no Match "" at end of line. */
> +#define ANY 3 /* no Match any one character. */
> +#define ANYOF 4 /* str Match any character in this string. */
> +#define ANYBUT 5 /* str Match any character not in this string. */
> +#define BRANCH 6 /* node Match this alternative, or the next... */
> +#define BACK 7 /* no Match "", "next" ptr points backward. */
> +#define EXACTLY 8 /* str Match this string. */
> +#define NOTHING 9 /* no Match empty string. */
> +#define STAR 10 /* node Match this (simple) thing 0 or more times. */
> +#define PLUS 11 /* node Match this (simple) thing 1 or more times. */
> +#define OPEN 20 /* no Mark this point in input as start of #n. */
> + /* OPEN+1 is number 1, etc. */
> +#define CLOSE 30 /* no Analogous to OPEN. */
> +
> +/*
> + * Opcode notes:
> + *
> + * BRANCH The set of branches constituting a single choice are hooked
> + * together with their "next" pointers, since precedence prevents
> + * anything being concatenated to any individual branch. The
> + * "next" pointer of the last BRANCH in a choice points to the
> + * thing following the whole choice. This is also where the
> + * final "next" pointer of each individual branch points; each
> + * branch starts with the operand node of a BRANCH node.
> + *
> + * BACK Normal "next" pointers all implicitly point forward; BACK
> + * exists to make loop structures possible.
> + *
> + * STAR,PLUS '?', and complex '*' and '+', are implemented as circular
> + * BRANCH structures using BACK. Simple cases (one character
> + * per match) are implemented with STAR and PLUS for speed
> + * and to minimize recursive plunges.
> + *
> + * OPEN,CLOSE ...are numbered at compile time.
> + */
> +
> +/*
> + * A node is one char of opcode followed by two chars of "next" pointer.
> + * "Next" pointers are stored as two 8-bit pieces, high order first. The
> + * value is a positive offset from the opcode of the node containing it.
> + * An operand, if any, simply follows the node. (Note that much of the
> + * code generation knows about this implicit relationship.)
> + *
> + * Using two bytes for the "next" pointer is vast overkill for most things,
> + * but allows patterns to get big without disasters.
> + */
> +#define OP(p) (*(p))
> +#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
> +#define OPERAND(p) ((p) + 3)
> +
> +/*
> + * See regmagic.h for one further detail of program structure.
> + */
> +
> +
> +/*
> + * Utility definitions.
> + */
> +#ifndef CHARBITS
> +#define UCHARAT(p) ((int)*(unsigned char *)(p))
> +#else
> +#define UCHARAT(p) ((int)*(p)&CHARBITS)
> +#endif
> +
> +#define FAIL(m) { regerror(m); return(NULL); }
> +#define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?')
> +#define META "^$.[()|?+*\\"
> +
> +/*
> + * Flags to be passed up and down.
> + */
> +#define HASWIDTH 01 /* Known never to match null string. */
> +#define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */
> +#define SPSTART 04 /* Starts with * or +. */
> +#define WORST 0 /* Worst case. */
> +
> +/*
> + * Global work variables for regcomp().
> + */
> +struct match_globals {
> +char *reginput; /* String-input pointer. */
> +char *regbol; /* Beginning of input, for ^ check. */
> +char **regstartp; /* Pointer to startp array. */
> +char **regendp; /* Ditto for endp. */
> +char *regparse; /* Input-scan pointer. */
> +int regnpar; /* () count. */
> +char regdummy;
> +char *regcode; /* Code-emit pointer; ®dummy = don't. */
> +long regsize; /* Code size. */
> +};
> +
> +/*
> + * Forward declarations for regcomp()'s friends.
> + */
> +#ifndef STATIC
> +#define STATIC static
> +#endif
> +STATIC char *reg(struct match_globals *g, int paren,int *flagp);
> +STATIC char *regbranch(struct match_globals *g, int *flagp);
> +STATIC char *regpiece(struct match_globals *g, int *flagp);
> +STATIC char *regatom(struct match_globals *g, int *flagp);
> +STATIC char *regnode(struct match_globals *g, char op);
> +STATIC char *regnext(struct match_globals *g, char *p);
> +STATIC void regc(struct match_globals *g, char b);
> +STATIC void reginsert(struct match_globals *g, char op, char *opnd);
> +STATIC void regtail(struct match_globals *g, char *p, char *val);
> +STATIC void regoptail(struct match_globals *g, char *p, char *val);
> +
> +
> +__kernel_size_t my_strcspn(const char *s1,const char *s2)
> +{
> + char *scan1;
> + char *scan2;
> + int count;
> +
> + count = 0;
> + for (scan1 = (char *)s1; *scan1 != '\0'; scan1++) {
> + for (scan2 = (char *)s2; *scan2 != '\0';) /* ++ moved down. */
> + if (*scan1 == *scan2++)
> + return(count);
> + count++;
> + }
> + return(count);
> +}
> +
> +/*
> + - regcomp - compile a regular expression into internal code
> + *
> + * We can't allocate space until we know how big the compiled form will be,
> + * but we can't compile it (and thus know how big it is) until we've got a
> + * place to put the code. So we cheat: we compile it twice, once with code
> + * generation turned off and size counting turned on, and once "for real".
> + * This also means that we don't allocate space until we are sure that the
> + * thing really will compile successfully, and we never have to move the
> + * code and thus invalidate pointers into it. (Note that it has to be in
> + * one piece because free() must be able to free it all.)
> + *
> + * Beware that the optimization-preparation code in here knows about some
> + * of the structure of the compiled regexp.
> + */
> +regexp *
> +regcomp(char *exp,int *patternsize)
> +{
> + register regexp *r;
> + register char *scan;
> + register char *longest;
> + register int len;
> + int flags;
> + struct match_globals g;
> +
> + /* commented out by ethan
> + extern char *malloc();
> + */
> +
> + if (exp == NULL)
> + FAIL("NULL argument");
> +
> + /* First pass: determine size, legality. */
> + g.regparse = exp;
> + g.regnpar = 1;
> + g.regsize = 0L;
> + g.regcode = &g.regdummy;
> + regc(&g, MAGIC);
> + if (reg(&g, 0, &flags) == NULL)
> + return(NULL);
> +
> + /* Small enough for pointer-storage convention? */
> + if (g.regsize >= 32767L) /* Probably could be 65535L. */
> + FAIL("regexp too big");
> +
> + /* Allocate space. */
> + *patternsize=sizeof(regexp) + (unsigned)g.regsize;
> + r = (regexp *)malloc(sizeof(regexp) + (unsigned)g.regsize);
> + if (r == NULL)
> + FAIL("out of space");
> +
> + /* Second pass: emit code. */
> + g.regparse = exp;
> + g.regnpar = 1;
> + g.regcode = r->program;
> + regc(&g, MAGIC);
> + if (reg(&g, 0, &flags) == NULL)
> + return(NULL);
> +
> + /* Dig out information for optimizations. */
> + r->regstart = '\0'; /* Worst-case defaults. */
> + r->reganch = 0;
> + r->regmust = NULL;
> + r->regmlen = 0;
> + scan = r->program+1; /* First BRANCH. */
> + if (OP(regnext(&g, scan)) == END) { /* Only one top-level choice. */
> + scan = OPERAND(scan);
> +
> + /* Starting-point info. */
> + if (OP(scan) == EXACTLY)
> + r->regstart = *OPERAND(scan);
> + else if (OP(scan) == BOL)
> + r->reganch++;
> +
> + /*
> + * If there's something expensive in the r.e., find the
> + * longest literal string that must appear and make it the
> + * regmust. Resolve ties in favor of later strings, since
> + * the regstart check works with the beginning of the r.e.
> + * and avoiding duplication strengthens checking. Not a
> + * strong reason, but sufficient in the absence of others.
> + */
> + if (flags&SPSTART) {
> + longest = NULL;
> + len = 0;
> + for (; scan != NULL; scan = regnext(&g, scan))
> + if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
> + longest = OPERAND(scan);
> + len = strlen(OPERAND(scan));
> + }
> + r->regmust = longest;
> + r->regmlen = len;
> + }
> + }
> +
> + return(r);
> +}
> +
> +/*
> + - reg - regular expression, i.e. main body or parenthesized thing
> + *
> + * Caller must absorb opening parenthesis.
> + *
> + * Combining parenthesis handling with the base level of regular expression
> + * is a trifle forced, but the need to tie the tails of the branches to what
> + * follows makes it hard to avoid.
> + */
> +static char *
> +reg(struct match_globals *g, int paren, int *flagp /* Parenthesized? */ )
> +{
> + register char *ret;
> + register char *br;
> + register char *ender;
> + register int parno = 0; /* 0 makes gcc happy */
> + int flags;
> +
> + *flagp = HASWIDTH; /* Tentatively. */
> +
> + /* Make an OPEN node, if parenthesized. */
> + if (paren) {
> + if (g->regnpar >= NSUBEXP)
> + FAIL("too many ()");
> + parno = g->regnpar;
> + g->regnpar++;
> + ret = regnode(g, OPEN+parno);
> + } else
> + ret = NULL;
> +
> + /* Pick up the branches, linking them together. */
> + br = regbranch(g, &flags);
> + if (br == NULL)
> + return(NULL);
> + if (ret != NULL)
> + regtail(g, ret, br); /* OPEN -> first. */
> + else
> + ret = br;
> + if (!(flags&HASWIDTH))
> + *flagp &= ~HASWIDTH;
> + *flagp |= flags&SPSTART;
> + while (*g->regparse == '|') {
> + g->regparse++;
> + br = regbranch(g, &flags);
> + if (br == NULL)
> + return(NULL);
> + regtail(g, ret, br); /* BRANCH -> BRANCH. */
> + if (!(flags&HASWIDTH))
> + *flagp &= ~HASWIDTH;
> + *flagp |= flags&SPSTART;
> + }
> +
> + /* Make a closing node, and hook it on the end. */
> + ender = regnode(g, (paren) ? CLOSE+parno : END);
> + regtail(g, ret, ender);
> +
> + /* Hook the tails of the branches to the closing node. */
> + for (br = ret; br != NULL; br = regnext(g, br))
> + regoptail(g, br, ender);
> +
> + /* Check for proper termination. */
> + if (paren && *g->regparse++ != ')') {
> + FAIL("unmatched ()");
> + } else if (!paren && *g->regparse != '\0') {
> + if (*g->regparse == ')') {
> + FAIL("unmatched ()");
> + } else
> + FAIL("junk on end"); /* "Can't happen". */
> + /* NOTREACHED */
> + }
> +
> + return(ret);
> +}
> +
> +/*
> + - regbranch - one alternative of an | operator
> + *
> + * Implements the concatenation operator.
> + */
> +static char *
> +regbranch(struct match_globals *g, int *flagp)
> +{
> + register char *ret;
> + register char *chain;
> + register char *latest;
> + int flags;
> +
> + *flagp = WORST; /* Tentatively. */
> +
> + ret = regnode(g, BRANCH);
> + chain = NULL;
> + while (*g->regparse != '\0' && *g->regparse != '|' && *g->regparse != ')') {
> + latest = regpiece(g, &flags);
> + if (latest == NULL)
> + return(NULL);
> + *flagp |= flags&HASWIDTH;
> + if (chain == NULL) /* First piece. */
> + *flagp |= flags&SPSTART;
> + else
> + regtail(g, chain, latest);
> + chain = latest;
> + }
> + if (chain == NULL) /* Loop ran zero times. */
> + (void) regnode(g, NOTHING);
> +
> + return(ret);
> +}
> +
> +/*
> + - regpiece - something followed by possible [*+?]
> + *
> + * Note that the branching code sequences used for ? and the general cases
> + * of * and + are somewhat optimized: they use the same NOTHING node as
> + * both the endmarker for their branch list and the body of the last branch.
> + * It might seem that this node could be dispensed with entirely, but the
> + * endmarker role is not redundant.
> + */
> +static char *
> +regpiece(struct match_globals *g, int *flagp)
> +{
> + register char *ret;
> + register char op;
> + register char *next;
> + int flags;
> +
> + ret = regatom(g, &flags);
> + if (ret == NULL)
> + return(NULL);
> +
> + op = *g->regparse;
> + if (!ISMULT(op)) {
> + *flagp = flags;
> + return(ret);
> + }
> +
> + if (!(flags&HASWIDTH) && op != '?')
> + FAIL("*+ operand could be empty");
> + *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
> +
> + if (op == '*' && (flags&SIMPLE))
> + reginsert(g, STAR, ret);
> + else if (op == '*') {
> + /* Emit x* as (x&|), where & means "self". */
> + reginsert(g, BRANCH, ret); /* Either x */
> + regoptail(g, ret, regnode(g, BACK)); /* and loop */
> + regoptail(g, ret, ret); /* back */
> + regtail(g, ret, regnode(g, BRANCH)); /* or */
> + regtail(g, ret, regnode(g, NOTHING)); /* null. */
> + } else if (op == '+' && (flags&SIMPLE))
> + reginsert(g, PLUS, ret);
> + else if (op == '+') {
> + /* Emit x+ as x(&|), where & means "self". */
> + next = regnode(g, BRANCH); /* Either */
> + regtail(g, ret, next);
> + regtail(g, regnode(g, BACK), ret); /* loop back */
> + regtail(g, next, regnode(g, BRANCH)); /* or */
> + regtail(g, ret, regnode(g, NOTHING)); /* null. */
> + } else if (op == '?') {
> + /* Emit x? as (x|) */
> + reginsert(g, BRANCH, ret); /* Either x */
> + regtail(g, ret, regnode(g, BRANCH)); /* or */
> + next = regnode(g, NOTHING); /* null. */
> + regtail(g, ret, next);
> + regoptail(g, ret, next);
> + }
> + g->regparse++;
> + if (ISMULT(*g->regparse))
> + FAIL("nested *?+");
> +
> + return(ret);
> +}
> +
> +/*
> + - regatom - the lowest level
> + *
> + * Optimization: gobbles an entire sequence of ordinary characters so that
> + * it can turn them into a single node, which is smaller to store and
> + * faster to run. Backslashed characters are exceptions, each becoming a
> + * separate node; the code is simpler that way and it's not worth fixing.
> + */
> +static char *
> +regatom(struct match_globals *g, int *flagp)
> +{
> + register char *ret;
> + int flags;
> +
> + *flagp = WORST; /* Tentatively. */
> +
> + switch (*g->regparse++) {
> + case '^':
> + ret = regnode(g, BOL);
> + break;
> + case '$':
> + ret = regnode(g, EOL);
> + break;
> + case '.':
> + ret = regnode(g, ANY);
> + *flagp |= HASWIDTH|SIMPLE;
> + break;
> + case '[': {
> + register int class;
> + register int classend;
> +
> + if (*g->regparse == '^') { /* Complement of range. */
> + ret = regnode(g, ANYBUT);
> + g->regparse++;
> + } else
> + ret = regnode(g, ANYOF);
> + if (*g->regparse == ']' || *g->regparse == '-')
> + regc(g, *g->regparse++);
> + while (*g->regparse != '\0' && *g->regparse != ']') {
> + if (*g->regparse == '-') {
> + g->regparse++;
> + if (*g->regparse == ']' || *g->regparse == '\0')
> + regc(g, '-');
> + else {
> + class = UCHARAT(g->regparse-2)+1;
> + classend = UCHARAT(g->regparse);
> + if (class > classend+1)
> + FAIL("invalid [] range");
> + for (; class <= classend; class++)
> + regc(g, class);
> + g->regparse++;
> + }
> + } else
> + regc(g, *g->regparse++);
> + }
> + regc(g, '\0');
> + if (*g->regparse != ']')
> + FAIL("unmatched []");
> + g->regparse++;
> + *flagp |= HASWIDTH|SIMPLE;
> + }
> + break;
> + case '(':
> + ret = reg(g, 1, &flags);
> + if (ret == NULL)
> + return(NULL);
> + *flagp |= flags&(HASWIDTH|SPSTART);
> + break;
> + case '\0':
> + case '|':
> + case ')':
> + FAIL("internal urp"); /* Supposed to be caught earlier. */
> + break;
> + case '?':
> + case '+':
> + case '*':
> + FAIL("?+* follows nothing");
> + break;
> + case '\\':
> + if (*g->regparse == '\0')
> + FAIL("trailing \\");
> + ret = regnode(g, EXACTLY);
> + regc(g, *g->regparse++);
> + regc(g, '\0');
> + *flagp |= HASWIDTH|SIMPLE;
> + break;
> + default: {
> + register int len;
> + register char ender;
> +
> + g->regparse--;
> + len = my_strcspn((const char *)g->regparse, (const char *)META);
> + if (len <= 0)
> + FAIL("internal disaster");
> + ender = *(g->regparse+len);
> + if (len > 1 && ISMULT(ender))
> + len--; /* Back off clear of ?+* operand. */
> + *flagp |= HASWIDTH;
> + if (len == 1)
> + *flagp |= SIMPLE;
> + ret = regnode(g, EXACTLY);
> + while (len > 0) {
> + regc(g, *g->regparse++);
> + len--;
> + }
> + regc(g, '\0');
> + }
> + break;
> + }
> +
> + return(ret);
> +}
> +
> +/*
> + - regnode - emit a node
> + */
> +static char * /* Location. */
> +regnode(struct match_globals *g, char op)
> +{
> + register char *ret;
> + register char *ptr;
> +
> + ret = g->regcode;
> + if (ret == &g->regdummy) {
> + g->regsize += 3;
> + return(ret);
> + }
> +
> + ptr = ret;
> + *ptr++ = op;
> + *ptr++ = '\0'; /* Null "next" pointer. */
> + *ptr++ = '\0';
> + g->regcode = ptr;
> +
> + return(ret);
> +}
> +
> +/*
> + - regc - emit (if appropriate) a byte of code
> + */
> +static void
> +regc(struct match_globals *g, char b)
> +{
> + if (g->regcode != &g->regdummy)
> + *g->regcode++ = b;
> + else
> + g->regsize++;
> +}
> +
> +/*
> + - reginsert - insert an operator in front of already-emitted operand
> + *
> + * Means relocating the operand.
> + */
> +static void
> +reginsert(struct match_globals *g, char op, char* opnd)
> +{
> + register char *src;
> + register char *dst;
> + register char *place;
> +
> + if (g->regcode == &g->regdummy) {
> + g->regsize += 3;
> + return;
> + }
> +
> + src = g->regcode;
> + g->regcode += 3;
> + dst = g->regcode;
> + while (src > opnd)
> + *--dst = *--src;
> +
> + place = opnd; /* Op node, where operand used to be. */
> + *place++ = op;
> + *place++ = '\0';
> + *place++ = '\0';
> +}
> +
> +/*
> + - regtail - set the next-pointer at the end of a node chain
> + */
> +static void
> +regtail(struct match_globals *g, char *p, char *val)
> +{
> + register char *scan;
> + register char *temp;
> + register int offset;
> +
> + if (p == &g->regdummy)
> + return;
> +
> + /* Find last node. */
> + scan = p;
> + for (;;) {
> + temp = regnext(g, scan);
> + if (temp == NULL)
> + break;
> + scan = temp;
> + }
> +
> + if (OP(scan) == BACK)
> + offset = scan - val;
> + else
> + offset = val - scan;
> + *(scan+1) = (offset>>8)&0377;
> + *(scan+2) = offset&0377;
> +}
> +
> +/*
> + - regoptail - regtail on operand of first argument; nop if operandless
> + */
> +static void
> +regoptail(struct match_globals *g, char *p, char *val)
> +{
> + /* "Operandless" and "op != BRANCH" are synonymous in practice. */
> + if (p == NULL || p == &g->regdummy || OP(p) != BRANCH)
> + return;
> + regtail(g, OPERAND(p), val);
> +}
> +
> +/*
> + * regexec and friends
> + */
> +
> +
> +/*
> + * Forwards.
> + */
> +STATIC int regtry(struct match_globals *g, regexp *prog, char *string);
> +STATIC int regmatch(struct match_globals *g, char *prog);
> +STATIC int regrepeat(struct match_globals *g, char *p);
> +
> +#ifdef DEBUG
> +int regnarrate = 0;
> +void regdump();
> +STATIC char *regprop(char *op);
> +#endif
> +
> +/*
> + - regexec - match a regexp against a string
> + */
> +int
> +regexec(regexp *prog, char *string)
> +{
> + register char *s;
> + struct match_globals g;
> +
> + /* Be paranoid... */
> + if (prog == NULL || string == NULL) {
> + printk("<3>Regexp: NULL parameter\n");
> + return(0);
> + }
> +
> + /* Check validity of program. */
> + if (UCHARAT(prog->program) != MAGIC) {
> + printk("<3>Regexp: corrupted program\n");
> + return(0);
> + }
> +
> + /* If there is a "must appear" string, look for it. */
> + if (prog->regmust != NULL) {
> + s = string;
> + while ((s = strchr(s, prog->regmust[0])) != NULL) {
> + if (strncmp(s, prog->regmust, prog->regmlen) == 0)
> + break; /* Found it. */
> + s++;
> + }
> + if (s == NULL) /* Not present. */
> + return(0);
> + }
> +
> + /* Mark beginning of line for ^ . */
> + g.regbol = string;
> +
> + /* Simplest case: anchored match need be tried only once. */
> + if (prog->reganch)
> + return(regtry(&g, prog, string));
> +
> + /* Messy cases: unanchored match. */
> + s = string;
> + if (prog->regstart != '\0')
> + /* We know what char it must start with. */
> + while ((s = strchr(s, prog->regstart)) != NULL) {
> + if (regtry(&g, prog, s))
> + return(1);
> + s++;
> + }
> + else
> + /* We don't -- general case. */
> + do {
> + if (regtry(&g, prog, s))
> + return(1);
> + } while (*s++ != '\0');
> +
> + /* Failure. */
> + return(0);
> +}
> +
> +/*
> + - regtry - try match at specific point
> + */
> +static int /* 0 failure, 1 success */
> +regtry(struct match_globals *g, regexp *prog, char *string)
> +{
> + register int i;
> + register char **sp;
> + register char **ep;
> +
> + g->reginput = string;
> + g->regstartp = prog->startp;
> + g->regendp = prog->endp;
> +
> + sp = prog->startp;
> + ep = prog->endp;
> + for (i = NSUBEXP; i > 0; i--) {
> + *sp++ = NULL;
> + *ep++ = NULL;
> + }
> + if (regmatch(g, prog->program + 1)) {
> + prog->startp[0] = string;
> + prog->endp[0] = g->reginput;
> + return(1);
> + } else
> + return(0);
> +}
> +
> +/*
> + - regmatch - main matching routine
> + *
> + * Conceptually the strategy is simple: check to see whether the current
> + * node matches, call self recursively to see whether the rest matches,
> + * and then act accordingly. In practice we make some effort to avoid
> + * recursion, in particular by going through "ordinary" nodes (that don't
> + * need to know whether the rest of the match failed) by a loop instead of
> + * by recursion.
> + */
> +static int /* 0 failure, 1 success */
> +regmatch(struct match_globals *g, char *prog)
> +{
> + register char *scan = prog; /* Current node. */
> + char *next; /* Next node. */
> +
> +#ifdef DEBUG
> + if (scan != NULL && regnarrate)
> + fprintf(stderr, "%s(\n", regprop(scan));
> +#endif
> + while (scan != NULL) {
> +#ifdef DEBUG
> + if (regnarrate)
> + fprintf(stderr, "%s...\n", regprop(scan));
> +#endif
> + next = regnext(g, scan);
> +
> + switch (OP(scan)) {
> + case BOL:
> + if (g->reginput != g->regbol)
> + return(0);
> + break;
> + case EOL:
> + if (*g->reginput != '\0')
> + return(0);
> + break;
> + case ANY:
> + if (*g->reginput == '\0')
> + return(0);
> + g->reginput++;
> + break;
> + case EXACTLY: {
> + register int len;
> + register char *opnd;
> +
> + opnd = OPERAND(scan);
> + /* Inline the first character, for speed. */
> + if (*opnd != *g->reginput)
> + return(0);
> + len = strlen(opnd);
> + if (len > 1 && strncmp(opnd, g->reginput, len) != 0)
> + return(0);
> + g->reginput += len;
> + }
> + break;
> + case ANYOF:
> + if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) == NULL)
> + return(0);
> + g->reginput++;
> + break;
> + case ANYBUT:
> + if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) != NULL)
> + return(0);
> + g->reginput++;
> + break;
> + case NOTHING:
> + case BACK:
> + break;
> + case OPEN+1:
> + case OPEN+2:
> + case OPEN+3:
> + case OPEN+4:
> + case OPEN+5:
> + case OPEN+6:
> + case OPEN+7:
> + case OPEN+8:
> + case OPEN+9: {
> + register int no;
> + register char *save;
> +
> + no = OP(scan) - OPEN;
> + save = g->reginput;
> +
> + if (regmatch(g, next)) {
> + /*
> + * Don't set startp if some later
> + * invocation of the same parentheses
> + * already has.
> + */
> + if (g->regstartp[no] == NULL)
> + g->regstartp[no] = save;
> + return(1);
> + } else
> + return(0);
> + }
> + break;
> + case CLOSE+1:
> + case CLOSE+2:
> + case CLOSE+3:
> + case CLOSE+4:
> + case CLOSE+5:
> + case CLOSE+6:
> + case CLOSE+7:
> + case CLOSE+8:
> + case CLOSE+9:
> + {
> + register int no;
> + register char *save;
> +
> + no = OP(scan) - CLOSE;
> + save = g->reginput;
> +
> + if (regmatch(g, next)) {
> + /*
> + * Don't set endp if some later
> + * invocation of the same parentheses
> + * already has.
> + */
> + if (g->regendp[no] == NULL)
> + g->regendp[no] = save;
> + return(1);
> + } else
> + return(0);
> + }
> + break;
> + case BRANCH: {
> + register char *save;
> +
> + if (OP(next) != BRANCH) /* No choice. */
> + next = OPERAND(scan); /* Avoid recursion. */
> + else {
> + do {
> + save = g->reginput;
> + if (regmatch(g, OPERAND(scan)))
> + return(1);
> + g->reginput = save;
> + scan = regnext(g, scan);
> + } while (scan != NULL && OP(scan) == BRANCH);
> + return(0);
> + /* NOTREACHED */
> + }
> + }
> + break;
> + case STAR:
> + case PLUS: {
> + register char nextch;
> + register int no;
> + register char *save;
> + register int min;
> +
> + /*
> + * Lookahead to avoid useless match attempts
> + * when we know what character comes next.
> + */
> + nextch = '\0';
> + if (OP(next) == EXACTLY)
> + nextch = *OPERAND(next);
> + min = (OP(scan) == STAR) ? 0 : 1;
> + save = g->reginput;
> + no = regrepeat(g, OPERAND(scan));
> + while (no >= min) {
> + /* If it could work, try it. */
> + if (nextch == '\0' || *g->reginput == nextch)
> + if (regmatch(g, next))
> + return(1);
> + /* Couldn't or didn't -- back up. */
> + no--;
> + g->reginput = save + no;
> + }
> + return(0);
> + }
> + break;
> + case END:
> + return(1); /* Success! */
> + break;
> + default:
> + printk("<3>Regexp: memory corruption\n");
> + return(0);
> + break;
> + }
> +
> + scan = next;
> + }
> +
> + /*
> + * We get here only if there's trouble -- normally "case END" is
> + * the terminating point.
> + */
> + printk("<3>Regexp: corrupted pointers\n");
> + return(0);
> +}
> +
> +/*
> + - regrepeat - repeatedly match something simple, report how many
> + */
> +static int
> +regrepeat(struct match_globals *g, char *p)
> +{
> + register int count = 0;
> + register char *scan;
> + register char *opnd;
> +
> + scan = g->reginput;
> + opnd = OPERAND(p);
> + switch (OP(p)) {
> + case ANY:
> + count = strlen(scan);
> + scan += count;
> + break;
> + case EXACTLY:
> + while (*opnd == *scan) {
> + count++;
> + scan++;
> + }
> + break;
> + case ANYOF:
> + while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
> + count++;
> + scan++;
> + }
> + break;
> + case ANYBUT:
> + while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
> + count++;
> + scan++;
> + }
> + break;
> + default: /* Oh dear. Called inappropriately. */
> + printk("<3>Regexp: internal foulup\n");
> + count = 0; /* Best compromise. */
> + break;
> + }
> + g->reginput = scan;
> +
> + return(count);
> +}
> +
> +/*
> + - regnext - dig the "next" pointer out of a node
> + */
> +static char*
> +regnext(struct match_globals *g, char *p)
> +{
> + register int offset;
> +
> + if (p == &g->regdummy)
> + return(NULL);
> +
> + offset = NEXT(p);
> + if (offset == 0)
> + return(NULL);
> +
> + if (OP(p) == BACK)
> + return(p-offset);
> + else
> + return(p+offset);
> +}
> +
> +#ifdef DEBUG
> +
> +STATIC char *regprop();
> +
> +/*
> + - regdump - dump a regexp onto stdout in vaguely comprehensible form
> + */
> +void
> +regdump(regexp *r)
> +{
> + register char *s;
> + register char op = EXACTLY; /* Arbitrary non-END op. */
> + register char *next;
> + /* extern char *strchr(); */
> +
> +
> + s = r->program + 1;
> + while (op != END) { /* While that wasn't END last time... */
> + op = OP(s);
> + printf("%2d%s", s-r->program, regprop(s)); /* Where, what. */
> + next = regnext(s);
> + if (next == NULL) /* Next ptr. */
> + printf("(0)");
> + else
> + printf("(%d)", (s-r->program)+(next-s));
> + s += 3;
> + if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
> + /* Literal string, where present. */
> + while (*s != '\0') {
> + putchar(*s);
> + s++;
> + }
> + s++;
> + }
> + putchar('\n');
> + }
> +
> + /* Header fields of interest. */
> + if (r->regstart != '\0')
> + printf("start `%c' ", r->regstart);
> + if (r->reganch)
> + printf("anchored ");
> + if (r->regmust != NULL)
> + printf("must have \"%s\"", r->regmust);
> + printf("\n");
> +}
> +
> +/*
> + - regprop - printable representation of opcode
> + */
> +static char *
> +regprop(char *op)
> +{
> +#define BUFLEN 50
> + register char *p;
> + static char buf[BUFLEN];
> +
> + strcpy(buf, ":");
> +
> + switch (OP(op)) {
> + case BOL:
> + p = "BOL";
> + break;
> + case EOL:
> + p = "EOL";
> + break;
> + case ANY:
> + p = "ANY";
> + break;
> + case ANYOF:
> + p = "ANYOF";
> + break;
> + case ANYBUT:
> + p = "ANYBUT";
> + break;
> + case BRANCH:
> + p = "BRANCH";
> + break;
> + case EXACTLY:
> + p = "EXACTLY";
> + break;
> + case NOTHING:
> + p = "NOTHING";
> + break;
> + case BACK:
> + p = "BACK";
> + break;
> + case END:
> + p = "END";
> + break;
> + case OPEN+1:
> + case OPEN+2:
> + case OPEN+3:
> + case OPEN+4:
> + case OPEN+5:
> + case OPEN+6:
> + case OPEN+7:
> + case OPEN+8:
> + case OPEN+9:
> + snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "OPEN%d", OP(op)-OPEN);
> + p = NULL;
> + break;
> + case CLOSE+1:
> + case CLOSE+2:
> + case CLOSE+3:
> + case CLOSE+4:
> + case CLOSE+5:
> + case CLOSE+6:
> + case CLOSE+7:
> + case CLOSE+8:
> + case CLOSE+9:
> + snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "CLOSE%d", OP(op)-CLOSE);
> + p = NULL;
> + break;
> + case STAR:
> + p = "STAR";
> + break;
> + case PLUS:
> + p = "PLUS";
> + break;
> + default:
> + printk("<3>Regexp: corrupted opcode\n");
> + break;
> + }
> + if (p != NULL)
> + strncat(buf, p, BUFLEN-strlen(buf));
> + return(buf);
> +}
> +#endif
> +
> +
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/regexp/regexp.h 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/regexp/regexp.h 2006-12-13 00:13:08.000000000 -0600
> @@ -0,0 +1,41 @@
> +/*
> + * Definitions etc. for regexp(3) routines.
> + *
> + * Caveat: this is V8 regexp(3) [actually, a reimplementation thereof],
> + * not the System V one.
> + */
> +
> +#ifndef REGEXP_H
> +#define REGEXP_H
> +
> +
> +/*
> +http://www.opensource.apple.com/darwinsource/10.3/expect-1/expect/expect.h ,
> +which contains a version of this library, says:
> +
> + *
> + * NSUBEXP must be at least 10, and no greater than 117 or the parser
> + * will not work properly.
> + *
> +
> +However, it looks rather like this library is limited to 10. If you think
> +otherwise, let us know.
> +*/
> +
> +#define NSUBEXP 10
> +typedef struct regexp {
> + char *startp[NSUBEXP];
> + char *endp[NSUBEXP];
> + char regstart; /* Internal use only. */
> + char reganch; /* Internal use only. */
> + char *regmust; /* Internal use only. */
> + int regmlen; /* Internal use only. */
> + char program[1]; /* Unwarranted chumminess with compiler. */
> +} regexp;
> +
> +regexp * regcomp(char *exp, int *patternsize);
> +int regexec(regexp *prog, char *string);
> +void regsub(regexp *prog, char *source, char *dest);
> +void regerror(char *s);
> +
> +#endif
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/regexp/regmagic.h 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/regexp/regmagic.h 2006-12-13 00:13:08.000000000 -0600
> @@ -0,0 +1,5 @@
> +/*
> + * The first byte of the regexp internal "program" is actually this magic
> + * number; the start node begins in the second byte.
> + */
> +#define MAGIC 0234
> --- linux-2.6.19.1-stock/net/ipv4/netfilter/regexp/regsub.c 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.19.1-layer7/net/ipv4/netfilter/regexp/regsub.c 2006-12-13 00:13:08.000000000 -0600
> @@ -0,0 +1,95 @@
> +/*
> + * regsub
> + * @(#)regsub.c 1.3 of 2 April 86
> + *
> + * Copyright (c) 1986 by University of Toronto.
> + * Written by Henry Spencer. Not derived from licensed software.
> + *
> + * Permission is granted to anyone to use this software for any
> + * purpose on any computer system, and to redistribute it freely,
> + * subject to the following restrictions:
> + *
> + * 1. The author is not responsible for the consequences of use of
> + * this software, no matter how awful, even if they arise
> + * from defects in it.
> + *
> + * 2. The origin of this software must not be misrepresented, either
> + * by explicit claim or by omission.
> + *
> + * 3. Altered versions must be plainly marked as such, and must not
> + * be misrepresented as being the original software.
> + *
> + *
> + * This code was modified by Ethan Sommer to work within the kernel
> + * (it now uses kmalloc etc..)
> + *
> + */
> +#include "regexp.h"
> +#include "regmagic.h"
> +#include <linux/string.h>
> +
> +
> +#ifndef CHARBITS
> +#define UCHARAT(p) ((int)*(unsigned char *)(p))
> +#else
> +#define UCHARAT(p) ((int)*(p)&CHARBITS)
> +#endif
> +
> +#if 0
> +//void regerror(char * s)
> +//{
> +// printk("regexp(3): %s", s);
> +// /* NOTREACHED */
> +//}
> +#endif
> +
> +/*
> + - regsub - perform substitutions after a regexp match
> + */
> +void
> +regsub(regexp * prog, char * source, char * dest)
> +{
> + register char *src;
> + register char *dst;
> + register char c;
> + register int no;
> + register int len;
> +
> + /* Not necessary and gcc doesn't like it -MLS */
> + /*extern char *strncpy();*/
> +
> + if (prog == NULL || source == NULL || dest == NULL) {
> + regerror("NULL parm to regsub");
> + return;
> + }
> + if (UCHARAT(prog->program) != MAGIC) {
> + regerror("damaged regexp fed to regsub");
> + return;
> + }
> +
> + src = source;
> + dst = dest;
> + while ((c = *src++) != '\0') {
> + if (c == '&')
> + no = 0;
> + else if (c == '\\' && '0' <= *src && *src <= '9')
> + no = *src++ - '0';
> + else
> + no = -1;
> +
> + if (no < 0) { /* Ordinary character. */
> + if (c == '\\' && (*src == '\\' || *src == '&'))
> + c = *src++;
> + *dst++ = c;
> + } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
> + len = prog->endp[no] - prog->startp[no];
> + (void) strncpy(dst, prog->startp[no], len);
> + dst += len;
> + if (len != 0 && *(dst-1) == '\0') { /* strncpy hit NUL. */
> + regerror("damaged match string");
> + return;
> + }
> + }
> + }
> + *dst++ = '\0';
> +}
>
>
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