ip6_tunnel: Fix missing tunnel encapsulation limit option

Craig Gallek · davem330 · commit 89a23c8b528b · 2017-05-01T14:52:45.000-04:00
The IPv6 tunneling code tries to insert IPV6_TLV_TNL_ENCAP_LIMIT and IPV6_TLV_PADN options when an encapsulation limit is defined (the default is a limit of 4). An MTU adjustment is done to account for these options as well. However, the options are never present in the generated packets. The issue appears to be a subtlety between IPV6_DSTOPTS and IPV6_RTHDRDSTOPTS defined in RFC 3542. When the IPIP tunnel driver was written, the encap limit options were included as IPV6_RTHDRDSTOPTS in dst0opt of struct ipv6_txoptions. Later, ipv6_push_nfrags_opts was (correctly) updated to require IPV6_RTHDR options when IPV6_RTHDRDSTOPTS are to be used. This caused the options to no longer be included in v6 encapsulated packets. The fix is to use IPV6_DSTOPTS (in dst1opt of struct ipv6_txoptions) instead. IPV6_DSTOPTS do not have the additional IPV6_RTHDR requirement. Fixes: 1df64a8: ("[IPV6]: Add ip6ip6 tunnel driver.") Fixes: 333fad5: ("[IPV6]: Support several new sockopt / ancillary data in Advanced API (RFC3542)") Signed-off-by: Craig Gallek <kraig@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
@@ -954,7 +954,7 @@ static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
 	opt->dst_opt[5] = IPV6_TLV_PADN;
 	opt->dst_opt[6] = 1;
 
-	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
+	opt->ops.dst1opt = (struct ipv6_opt_hdr *) opt->dst_opt;
 	opt->ops.opt_nflen = 8;
 }
 
@@ -1178,7 +1178,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 
 	if (encap_limit >= 0) {
 		init_tel_txopt(&opt, encap_limit);
-		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL, NULL);
+		ipv6_push_frag_opts(skb, &opt.ops, &proto);
 	}
 
 	/* Calculate max headroom for all the headers and adjust

Original file line number	Diff line number	Diff line change
`@@ -954,7 +954,7 @@ static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)`
`954`	`954`	`opt->dst_opt[5] = IPV6_TLV_PADN;`
`955`	`955`	`opt->dst_opt[6] = 1;`
`956`	`956`
`957`		`- opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;`
	`957`	`+ opt->ops.dst1opt = (struct ipv6_opt_hdr *) opt->dst_opt;`
`958`	`958`	`opt->ops.opt_nflen = 8;`
`959`	`959`	`}`
`960`	`960`
`@@ -1178,7 +1178,7 @@ int ip6_tnl_xmit(struct sk_buff skb, struct net_device dev, __u8 dsfield,`
`1178`	`1178`
`1179`	`1179`	`if (encap_limit >= 0) {`
`1180`	`1180`	`init_tel_txopt(&opt, encap_limit);`
`1181`		`- ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL, NULL);`
	`1181`	`+ ipv6_push_frag_opts(skb, &opt.ops, &proto);`
`1182`	`1182`	`}`
`1183`	`1183`
`1184`	`1184`	`/* Calculate max headroom for all the headers and adjust`