提交 b777e0ce 编写于 作者: P Patrick McHardy 提交者: David S. Miller

[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: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 1bd9bef6
......@@ -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))
......
......@@ -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;
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);
int protohdr;
unsigned short _frag_off;
currenthdr = hp->nexthdr;
ptr += hdrlen;
/* ptr is too large */
if ( ptr > skb->len )
return 0;
if (_fragoff) {
if (ip6t_ext_hdr(currenthdr))
protohdr = ipv6_find_hdr(skb, protoff, -1, &_frag_off);
if (protohdr < 0)
return 0;
break;
}
}
*protoff = ptr;
*fragoff = _fragoff;
/* 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);
......
......@@ -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);
......
......@@ -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;
......
......@@ -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);
......
......@@ -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);
......
......@@ -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;
......
......@@ -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);
......
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