From b777e0ce7437a0e788e2aeb42aca9af2cce1f2e1 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 5 Jan 2006 12:21:16 -0800 Subject: [PATCH] [NETFILTER]: make ipv6_find_hdr() find transport protocol header The original ipv6_find_hdr() finds the specified header in IPv6 packets. This makes it possible to get transport header so that we can kill similar loop in ip6_match_packet(). Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/netfilter_ipv6/ip6_tables.h | 2 +- net/ipv6/netfilter/ip6_tables.c | 106 ++++++++-------------- net/ipv6/netfilter/ip6t_ah.c | 2 +- net/ipv6/netfilter/ip6t_dst.c | 4 +- net/ipv6/netfilter/ip6t_esp.c | 2 +- net/ipv6/netfilter/ip6t_frag.c | 2 +- net/ipv6/netfilter/ip6t_hbh.c | 4 +- net/ipv6/netfilter/ip6t_rt.c | 2 +- 8 files changed, 49 insertions(+), 75 deletions(-) diff --git a/include/linux/netfilter_ipv6/ip6_tables.h b/include/linux/netfilter_ipv6/ip6_tables.h index 2efc046d9e94..a291cb76ef18 100644 --- a/include/linux/netfilter_ipv6/ip6_tables.h +++ b/include/linux/netfilter_ipv6/ip6_tables.h @@ -474,7 +474,7 @@ extern unsigned int ip6t_do_table(struct sk_buff **pskb, extern int ip6t_ext_hdr(u8 nexthdr); /* find specified header and get offset to it */ extern int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, - u8 target); + int target, unsigned short *fragoff); #define IP6T_ALIGN(s) (((s) + (__alignof__(struct ip6t_entry)-1)) & ~(__alignof__(struct ip6t_entry)-1)) diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index ea43ef1d94a7..13b1a525b92c 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -205,69 +205,21 @@ ip6_packet_match(const struct sk_buff *skb, /* look for the desired protocol header */ if((ip6info->flags & IP6T_F_PROTO)) { - u_int8_t currenthdr = ipv6->nexthdr; - struct ipv6_opt_hdr _hdr, *hp; - u_int16_t ptr; /* Header offset in skb */ - u_int16_t hdrlen; /* Header */ - u_int16_t _fragoff = 0, *fp = NULL; - - ptr = IPV6_HDR_LEN; - - while (ip6t_ext_hdr(currenthdr)) { - /* Is there enough space for the next ext header? */ - if (skb->len - ptr < IPV6_OPTHDR_LEN) - return 0; - - /* NONE or ESP: there isn't protocol part */ - /* If we want to count these packets in '-p all', - * we will change the return 0 to 1*/ - if ((currenthdr == IPPROTO_NONE) || - (currenthdr == IPPROTO_ESP)) - break; + int protohdr; + unsigned short _frag_off; - hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr); - BUG_ON(hp == NULL); - - /* Size calculation */ - if (currenthdr == IPPROTO_FRAGMENT) { - fp = skb_header_pointer(skb, - ptr+offsetof(struct frag_hdr, - frag_off), - sizeof(_fragoff), - &_fragoff); - if (fp == NULL) - return 0; - - _fragoff = ntohs(*fp) & ~0x7; - hdrlen = 8; - } else if (currenthdr == IPPROTO_AH) - hdrlen = (hp->hdrlen+2)<<2; - else - hdrlen = ipv6_optlen(hp); - - currenthdr = hp->nexthdr; - ptr += hdrlen; - /* ptr is too large */ - if ( ptr > skb->len ) - return 0; - if (_fragoff) { - if (ip6t_ext_hdr(currenthdr)) - return 0; - break; - } - } - - *protoff = ptr; - *fragoff = _fragoff; + protohdr = ipv6_find_hdr(skb, protoff, -1, &_frag_off); + if (protohdr < 0) + return 0; - /* currenthdr contains the protocol header */ + *fragoff = _frag_off; dprintf("Packet protocol %hi ?= %s%hi.\n", - currenthdr, + protohdr, ip6info->invflags & IP6T_INV_PROTO ? "!":"", ip6info->proto); - if (ip6info->proto == currenthdr) { + if (ip6info->proto == protohdr) { if(ip6info->invflags & IP6T_INV_PROTO) { return 0; } @@ -2098,26 +2050,39 @@ static void __exit fini(void) } /* - * find specified header up to transport protocol header. - * If found target header, the offset to the header is set to *offset - * and return 0. otherwise, return -1. + * find the offset to specified header or the protocol number of last header + * if target < 0. "last header" is transport protocol header, ESP, or + * "No next header". + * + * If target header is found, its offset is set in *offset and return protocol + * number. Otherwise, return -1. + * + * Note that non-1st fragment is special case that "the protocol number + * of last header" is "next header" field in Fragment header. In this case, + * *offset is meaningless and fragment offset is stored in *fragoff if fragoff + * isn't NULL. * - * Notes: - non-1st Fragment Header isn't skipped. - * - ESP header isn't skipped. - * - The target header may be trancated. */ -int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, u8 target) +int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, + int target, unsigned short *fragoff) { unsigned int start = (u8*)(skb->nh.ipv6h + 1) - skb->data; u8 nexthdr = skb->nh.ipv6h->nexthdr; unsigned int len = skb->len - start; + if (fragoff) + *fragoff = 0; + while (nexthdr != target) { struct ipv6_opt_hdr _hdr, *hp; unsigned int hdrlen; - if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) + if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) { + if (target < 0) + break; return -1; + } + hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr); if (hp == NULL) return -1; @@ -2131,8 +2096,17 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, u8 target) if (fp == NULL) return -1; - if (ntohs(*fp) & ~0x7) + _frag_off = ntohs(*fp) & ~0x7; + if (_frag_off) { + if (target < 0 && + ((!ipv6_ext_hdr(hp->nexthdr)) || + nexthdr == NEXTHDR_NONE)) { + if (fragoff) + *fragoff = _frag_off; + return hp->nexthdr; + } return -1; + } hdrlen = 8; } else if (nexthdr == NEXTHDR_AUTH) hdrlen = (hp->hdrlen + 2) << 2; @@ -2145,7 +2119,7 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, u8 target) } *offset = start; - return 0; + return nexthdr; } EXPORT_SYMBOL(ip6t_register_table); diff --git a/net/ipv6/netfilter/ip6t_ah.c b/net/ipv6/netfilter/ip6t_ah.c index 268918d5deea..f5c1a7ff4a1f 100644 --- a/net/ipv6/netfilter/ip6t_ah.c +++ b/net/ipv6/netfilter/ip6t_ah.c @@ -54,7 +54,7 @@ match(const struct sk_buff *skb, unsigned int ptr; unsigned int hdrlen = 0; - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL) < 0) return 0; ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); diff --git a/net/ipv6/netfilter/ip6t_dst.c b/net/ipv6/netfilter/ip6t_dst.c index c450a635e54b..48cf5f9efc95 100644 --- a/net/ipv6/netfilter/ip6t_dst.c +++ b/net/ipv6/netfilter/ip6t_dst.c @@ -71,9 +71,9 @@ match(const struct sk_buff *skb, unsigned int optlen; #if HOPBYHOP - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_HOP) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_HOP, NULL) < 0) #else - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_DEST) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_DEST, NULL) < 0) #endif return 0; diff --git a/net/ipv6/netfilter/ip6t_esp.c b/net/ipv6/netfilter/ip6t_esp.c index 65937de1b58c..e1828f6d0a40 100644 --- a/net/ipv6/netfilter/ip6t_esp.c +++ b/net/ipv6/netfilter/ip6t_esp.c @@ -56,7 +56,7 @@ match(const struct sk_buff *skb, /* Make sure this isn't an evil packet */ /*DEBUGP("ipv6_esp entered \n");*/ - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_ESP) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_ESP, NULL) < 0) return 0; eh = skb_header_pointer(skb, ptr, sizeof(_esp), &_esp); diff --git a/net/ipv6/netfilter/ip6t_frag.c b/net/ipv6/netfilter/ip6t_frag.c index 085d5f8eea29..d1549b268669 100644 --- a/net/ipv6/netfilter/ip6t_frag.c +++ b/net/ipv6/netfilter/ip6t_frag.c @@ -52,7 +52,7 @@ match(const struct sk_buff *skb, const struct ip6t_frag *fraginfo = matchinfo; unsigned int ptr; - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_FRAGMENT) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_FRAGMENT, NULL) < 0) return 0; fh = skb_header_pointer(skb, ptr, sizeof(_frag), &_frag); diff --git a/net/ipv6/netfilter/ip6t_hbh.c b/net/ipv6/netfilter/ip6t_hbh.c index 1d09485111d0..e3bc8e2700e7 100644 --- a/net/ipv6/netfilter/ip6t_hbh.c +++ b/net/ipv6/netfilter/ip6t_hbh.c @@ -71,9 +71,9 @@ match(const struct sk_buff *skb, unsigned int optlen; #if HOPBYHOP - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_HOP) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_HOP, NULL) < 0) #else - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_DEST) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_DEST, NULL) < 0) #endif return 0; diff --git a/net/ipv6/netfilter/ip6t_rt.c b/net/ipv6/netfilter/ip6t_rt.c index beb2fd5cebbb..c1e770e45543 100644 --- a/net/ipv6/netfilter/ip6t_rt.c +++ b/net/ipv6/netfilter/ip6t_rt.c @@ -58,7 +58,7 @@ match(const struct sk_buff *skb, unsigned int ret = 0; struct in6_addr *ap, _addr; - if (ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING) < 0) + if (ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL) < 0) return 0; rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route); -- 2.20.1