ipv4: Add ICMPv6 support when parse route ipproto [Linux 5.0]

This Linux kernel change "ipv4: Add ICMPv6 support when parse route ipproto" is included in the Linux 5.0 release. This change is authored by Hangbin Liu <liuhangbin [at] gmail.com> on Wed Feb 27 16:15:29 2019 +0800. The commit for this change in Linux stable tree is 5e1a99e (patch).

ipv4: Add ICMPv6 support when parse route ipproto

For ip rules, we need to use 'ipproto ipv6-icmp' to match ICMPv6 headers.
But for ip -6 route, currently we only support tcp, udp and icmp.

Add ICMPv6 support so we can match ipv6-icmp rules for route lookup.

v2: As David Ahern and Sabrina Dubroca suggested, Add an argument to
rtm_getroute_parse_ip_proto() to handle ICMP/ICMPv6 with different family.

Reported-by: Jianlin Shi <[email protected]>
Fixes: eacb9384a3fe ("ipv6: support sport, dport and ip_proto in RTM_GETROUTE")
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

There are 24 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 include/net/ip.h   |  2 +-
 net/ipv4/netlink.c | 17 +++++++++++++----
 net/ipv4/route.c   |  2 +-
 net/ipv6/route.c   |  3 ++-
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index f0e8d06..be3cad9 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -718,7 +718,7 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 int ip_misc_proc_init(void);
 #endif

-int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto,
+int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
                struct netlink_ext_ack *extack);

 #endif /* _IP_H */
diff --git a/net/ipv4/netlink.c b/net/ipv4/netlink.c
index f86bb4f..d8e3a1f 100644
--- a/net/ipv4/netlink.c
+++ b/net/ipv4/netlink.c
@@ -3,9 +3,10 @@
 #include <linux/types.h>
 #include <net/net_namespace.h>
 #include <net/netlink.h>
+#include <linux/in6.h>
 #include <net/ip.h>

-int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto,
+int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
                struct netlink_ext_ack *extack)
 {
    *ip_proto = nla_get_u8(attr);
@@ -13,11 +14,19 @@ int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto,
    switch (*ip_proto) {
    case IPPROTO_TCP:
    case IPPROTO_UDP:
+       return 0;
    case IPPROTO_ICMP:
+       if (family != AF_INET)
+           break;
+       return 0;
+#if IS_ENABLED(CONFIG_IPV6)
+   case IPPROTO_ICMPV6:
+       if (family != AF_INET6)
+           break;
        return 0;
-   default:
-       NL_SET_ERR_MSG(extack, "Unsupported ip proto");
-       return -EOPNOTSUPP;
+#endif
    }
+   NL_SET_ERR_MSG(extack, "Unsupported ip proto");
+   return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL_GPL(rtm_getroute_parse_ip_proto);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5163b64..7bb9128 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2803,7 +2803,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,

    if (tb[RTA_IP_PROTO]) {
        err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
-                         &ip_proto, extack);
+                         &ip_proto, AF_INET, extack);
        if (err)
            return err;
    }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b7a6200..8dad1d6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4893,7 +4893,8 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,

    if (tb[RTA_IP_PROTO]) {
        err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
-                         &fl6.flowi6_proto, extack);
+                         &fl6.flowi6_proto, AF_INET6,
+                         extack);
        if (err)
            goto errout;
    }

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