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Commit 9195bb8e authored by Ansis Atteka's avatar Ansis Atteka Committed by Jesse Gross
Browse files

ipv6: improve ipv6_find_hdr() to skip empty routing headers 



This patch prepares ipv6_find_hdr() function so that it could be
able to skip routing headers, where segements_left is 0. This is
required to handle multiple routing header case correctly when
changing IPv6 addresses.

Signed-off-by: default avatarAnsis Atteka <aatteka@nicira.com>
Signed-off-by: default avatarJesse Gross <jesse@nicira.com>
parent f8f62675

include/net/ipv6.h

+3 −2
Original line number Diff line number Diff line
@@ -633,6 +633,7 @@ extern bool ipv6_ext_hdr(u8 nexthdr); 
enum {

	IP6_FH_F_FRAG		= (1 << 0),

	IP6_FH_F_AUTH		= (1 << 1),

	IP6_FH_F_SKIP_RH	= (1 << 2),

};



/* find specified header and get offset to it */

net/ipv6/exthdrs_core.c

+28 −8
Original line number Diff line number Diff line
@@ -132,9 +132,11 @@ EXPORT_SYMBOL(ipv6_skip_exthdr); 
 * *offset is meaningless and fragment offset is stored in *fragoff if fragoff

 * isn't NULL.

 *

 * if flags is not NULL and it's a fragment, then the frag flag IP6_FH_F_FRAG

 * will be set. If it's an AH header, the IP6_FH_F_AUTH flag is set and

 * target < 0, then this function will stop at the AH header.

 * if flags is not NULL and it's a fragment, then the frag flag

 * IP6_FH_F_FRAG will be set. If it's an AH header, the

 * IP6_FH_F_AUTH flag is set and target < 0, then this function will

 * stop at the AH header. If IP6_FH_F_SKIP_RH flag was passed, then this

 * function will skip all those routing headers, where segements_left was 0.

 */

int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,

		  int target, unsigned short *fragoff, int *flags)
@@ -142,6 +144,7 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, 
	unsigned int start = skb_network_offset(skb) + sizeof(struct ipv6hdr);

	u8 nexthdr = ipv6_hdr(skb)->nexthdr;

	unsigned int len;

	bool found;



	if (fragoff)

		*fragoff = 0;
@@ -159,9 +162,10 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, 
	}

	len = skb->len - start;



	while (nexthdr != target) {

	do {

		struct ipv6_opt_hdr _hdr, *hp;

		unsigned int hdrlen;

		found = (nexthdr == target);



		if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {

			if (target < 0)
@@ -172,6 +176,20 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, 
		hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);

		if (hp == NULL)

			return -EBADMSG;



		if (nexthdr == NEXTHDR_ROUTING) {

			struct ipv6_rt_hdr _rh, *rh;



			rh = skb_header_pointer(skb, start, sizeof(_rh),

						&_rh);

			if (rh == NULL)

				return -EBADMSG;



			if (flags && (*flags & IP6_FH_F_SKIP_RH) &&

			    rh->segments_left == 0)

				found = false;

		}



		if (nexthdr == NEXTHDR_FRAGMENT) {

			unsigned short _frag_off;

			__be16 *fp;
@@ -205,10 +223,12 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, 
		} else

			hdrlen = ipv6_optlen(hp);



		if (!found) {

			nexthdr = hp->nexthdr;

			len -= hdrlen;

			start += hdrlen;

		}

	} while (!found);



	*offset = start;

	return nexthdr;