[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 <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netfilter_ipv6/ip6_tables.h b/include/linux/netfilter_ipv6/ip6_tables.h
index 2efc046..a291cb7 100644 (file)
--- 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 ea43ef1..13b1a52 100644 (file)
--- 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 268918d..f5c1a7f 100644 (file)
--- 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 c450a63..48cf5f9 100644 (file)
--- 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 65937de..e1828f6 100644 (file)
--- 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 085d5f8..d1549b2 100644 (file)
--- 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 1d09485..e3bc8e2 100644 (file)
--- 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 beb2fd5..c1e770e 100644 (file)
--- 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);