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authorPedro Ribeiro <pribeiro@net.ipl.pt>2008-10-15 18:47:49 -0400
committerDavid S. Miller <davem@davemloft.net>2008-10-15 19:03:01 -0400
commit22441cfa0c70dcd457f3c081fcf285c3bd155824 (patch)
treec313183f0b7a9c3736d5b042f8e97780d7670609
parentdeb28d9bc4bb6922c1f7e459744d7b2d0db3a1d2 (diff)
IPV6: Fix default gateway criteria wrt. HIGH/LOW preference radv option
Problem observed: In IPv6, in the presence of multiple routers candidates to default gateway in one segment, each sending a different value of preference, the Linux hosts connected to the segment weren't selecting the right one in all the combinations possible of LOW/MEDIUM/HIGH preference. This patch changes two files: include/linux/icmpv6.h Get the "router_pref" bitfield in the right place (as RFC4191 says), named the bit left with this fix as "home_agent" (RFC3775 say that's his function) net/ipv6/ndisc.c Corrects the binary logic behind the updating of the router preference in the flags of the routing table Result: With this two fixes applied, the default route used by the system was to consistent with the rules mentioned in RFC4191 in case of changes in the value of preference in router advertisements Signed-off-by: Pedro Ribeiro <pribeiro@net.ipl.pt> Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/icmpv6.h6
-rw-r--r--net/ipv6/ndisc.c2
2 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h
index 03067443198a..a93a8dd33118 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -40,16 +40,18 @@ struct icmp6hdr {
40 struct icmpv6_nd_ra { 40 struct icmpv6_nd_ra {
41 __u8 hop_limit; 41 __u8 hop_limit;
42#if defined(__LITTLE_ENDIAN_BITFIELD) 42#if defined(__LITTLE_ENDIAN_BITFIELD)
43 __u8 reserved:4, 43 __u8 reserved:3,
44 router_pref:2, 44 router_pref:2,
45 home_agent:1,
45 other:1, 46 other:1,
46 managed:1; 47 managed:1;
47 48
48#elif defined(__BIG_ENDIAN_BITFIELD) 49#elif defined(__BIG_ENDIAN_BITFIELD)
49 __u8 managed:1, 50 __u8 managed:1,
50 other:1, 51 other:1,
52 home_agent:1,
51 router_pref:2, 53 router_pref:2,
52 reserved:4; 54 reserved:3;
53#else 55#else
54#error "Please fix <asm/byteorder.h>" 56#error "Please fix <asm/byteorder.h>"
55#endif 57#endif
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 840b15780a36..aae7ddcc8a2e 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1199,7 +1199,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
1199 } 1199 }
1200 neigh->flags |= NTF_ROUTER; 1200 neigh->flags |= NTF_ROUTER;
1201 } else if (rt) { 1201 } else if (rt) {
1202 rt->rt6i_flags |= (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref); 1202 rt->rt6i_flags = (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
1203 } 1203 }
1204 1204
1205 if (rt) 1205 if (rt)