diff options
Diffstat (limited to 'net/ipv4/netfilter/ipt_tcpmss.c')
-rw-r--r-- | net/ipv4/netfilter/ipt_tcpmss.c | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/net/ipv4/netfilter/ipt_tcpmss.c b/net/ipv4/netfilter/ipt_tcpmss.c deleted file mode 100644 index 4dc9b16..0000000 --- a/net/ipv4/netfilter/ipt_tcpmss.c +++ /dev/null @@ -1,127 +0,0 @@ -/* Kernel module to match TCP MSS values. */ - -/* Copyright (C) 2000 Marc Boucher <marc@mbsi.ca> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - */ - -#include <linux/module.h> -#include <linux/skbuff.h> -#include <net/tcp.h> - -#include <linux/netfilter_ipv4/ipt_tcpmss.h> -#include <linux/netfilter_ipv4/ip_tables.h> - -#define TH_SYN 0x02 - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>"); -MODULE_DESCRIPTION("iptables TCP MSS match module"); - -/* Returns 1 if the mss option is set and matched by the range, 0 otherwise */ -static inline int -mssoption_match(u_int16_t min, u_int16_t max, - const struct sk_buff *skb, - int invert, - int *hotdrop) -{ - struct tcphdr _tcph, *th; - /* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */ - u8 _opt[15 * 4 - sizeof(_tcph)], *op; - unsigned int i, optlen; - - /* If we don't have the whole header, drop packet. */ - th = skb_header_pointer(skb, skb->nh.iph->ihl * 4, - sizeof(_tcph), &_tcph); - if (th == NULL) - goto dropit; - - /* Malformed. */ - if (th->doff*4 < sizeof(*th)) - goto dropit; - - optlen = th->doff*4 - sizeof(*th); - if (!optlen) - goto out; - - /* Truncated options. */ - op = skb_header_pointer(skb, skb->nh.iph->ihl * 4 + sizeof(*th), - optlen, _opt); - if (op == NULL) - goto dropit; - - for (i = 0; i < optlen; ) { - if (op[i] == TCPOPT_MSS - && (optlen - i) >= TCPOLEN_MSS - && op[i+1] == TCPOLEN_MSS) { - u_int16_t mssval; - - mssval = (op[i+2] << 8) | op[i+3]; - - return (mssval >= min && mssval <= max) ^ invert; - } - if (op[i] < 2) i++; - else i += op[i+1]?:1; - } -out: - return invert; - - dropit: - *hotdrop = 1; - return 0; -} - -static int -match(const struct sk_buff *skb, - const struct net_device *in, - const struct net_device *out, - const void *matchinfo, - int offset, - int *hotdrop) -{ - const struct ipt_tcpmss_match_info *info = matchinfo; - - return mssoption_match(info->mss_min, info->mss_max, skb, - info->invert, hotdrop); -} - -static int -checkentry(const char *tablename, - const struct ipt_ip *ip, - void *matchinfo, - unsigned int matchsize, - unsigned int hook_mask) -{ - if (matchsize != IPT_ALIGN(sizeof(struct ipt_tcpmss_match_info))) - return 0; - - /* Must specify -p tcp */ - if (ip->proto != IPPROTO_TCP || (ip->invflags & IPT_INV_PROTO)) { - printk("tcpmss: Only works on TCP packets\n"); - return 0; - } - - return 1; -} - -static struct ipt_match tcpmss_match = { - .name = "tcpmss", - .match = &match, - .checkentry = &checkentry, - .me = THIS_MODULE, -}; - -static int __init init(void) -{ - return ipt_register_match(&tcpmss_match); -} - -static void __exit fini(void) -{ - ipt_unregister_match(&tcpmss_match); -} - -module_init(init); -module_exit(fini); |