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ipv6: sr: add support for ip4ip6 encapsulation

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This patch enables the SRv6 encapsulation mode to carry an IPv4 payload.
All the infrastructure was already present, I just had to add a parameter
to seg6_do_srh_encap() to specify the inner packet protocol, and perform
some additional checks.

Usage example:
ip route add 1.2.3.4 encap seg6 mode encap segs fc00::1,fc00::2 dev eth0

Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Lebrun 2017-08-25 09:56:44 +02:00 committed by David S. Miller
parent 3fd8712707
commit 32d99d0b67
3 changed files with 40 additions and 12 deletions
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3
include/net/seg6.h
View file

@ -60,7 +60,8 @@ extern int seg6_local_init(void);
extern void seg6_local_exit(void);
extern bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len);
extern int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh);
extern int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
int proto);
extern int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh);
#endif

47
net/ipv6/seg6_iptunnel.c
View file

@ -91,7 +91,7 @@ static void set_tun_src(struct net *net, struct net_device *dev,
}
/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
{
struct net *net = dev_net(skb_dst(skb)->dev);
struct ipv6hdr *hdr, *inner_hdr;
@ -116,15 +116,22 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
* hlim will be decremented in ip6_forward() afterwards and
* decapsulation will overwrite inner hlim with outer hlim
*/
ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
ip6_flowlabel(inner_hdr));
hdr->hop_limit = inner_hdr->hop_limit;
if (skb->protocol == htons(ETH_P_IPV6)) {
ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
ip6_flowlabel(inner_hdr));
hdr->hop_limit = inner_hdr->hop_limit;
} else {
ip6_flow_hdr(hdr, 0, 0);
hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
}
hdr->nexthdr = NEXTHDR_ROUTING;
isrh = (void *)hdr + sizeof(*hdr);
memcpy(isrh, osrh, hdrlen);
isrh->nexthdr = NEXTHDR_IPV6;
isrh->nexthdr = proto;
hdr->daddr = isrh->segments[isrh->first_segment];
set_tun_src(net, skb->dev, &hdr->daddr, &hdr->saddr);
@ -199,7 +206,7 @@ static int seg6_do_srh(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct seg6_iptunnel_encap *tinfo;
int err = 0;
int proto, err = 0;
tinfo = seg6_encap_lwtunnel(dst->lwtstate);
@ -210,17 +217,31 @@ static int seg6_do_srh(struct sk_buff *skb)
switch (tinfo->mode) {
case SEG6_IPTUN_MODE_INLINE:
if (skb->protocol != htons(ETH_P_IPV6))
return -EINVAL;
err = seg6_do_srh_inline(skb, tinfo->srh);
if (err)
return err;
skb_reset_inner_headers(skb);
break;
case SEG6_IPTUN_MODE_ENCAP:
err = seg6_do_srh_encap(skb, tinfo->srh);
if (skb->protocol == htons(ETH_P_IPV6))
proto = IPPROTO_IPV6;
else if (skb->protocol == htons(ETH_P_IP))
proto = IPPROTO_IPIP;
else
return -EINVAL;
err = seg6_do_srh_encap(skb, tinfo->srh, proto);
if (err)
return err;
skb->protocol = htons(ETH_P_IPV6);
break;
}
if (err)
return err;
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
@ -334,6 +355,9 @@ static int seg6_build_state(struct nlattr *nla,
struct seg6_lwt *slwt;
int err;
if (family != AF_INET && family != AF_INET6)
return -EINVAL;
err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
seg6_iptunnel_policy, extack);
@ -356,6 +380,9 @@ static int seg6_build_state(struct nlattr *nla,
switch (tuninfo->mode) {
case SEG6_IPTUN_MODE_INLINE:
if (family != AF_INET6)
return -EINVAL;
break;
case SEG6_IPTUN_MODE_ENCAP:
break;

2
net/ipv6/seg6_local.c
View file

@ -290,7 +290,7 @@ static int input_action_end_b6_encap(struct sk_buff *skb,
skb_reset_inner_headers(skb);
skb->encapsulation = 1;
err = seg6_do_srh_encap(skb, slwt->srh);
err = seg6_do_srh_encap(skb, slwt->srh, IPPROTO_IPV6);
if (err)
goto drop;