net: ping6: support setting basic SOL_IPV6 options via cmsg

Support setting IPV6_HOPLIMIT, IPV6_TCLASS, IPV6_DONTFRAG
during sendmsg via SOL_IPV6 cmsgs.

tclass and dontfrag are init'ed from struct ipv6_pinfo in
ipcm6_init_sk(), while hlimit is inited to -1, so we need
to handle it being populated via cmsg explicitly.

Leave extension headers and flowlabel unimplemented.
Those are slightly more laborious to test and users
seem to primarily care about IPV6_TCLASS.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0c6c971..3286b64 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1487,6 +1487,7 @@ static int __ip6_append_data(struct sock *sk,
 
        if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
            (sk->sk_protocol == IPPROTO_UDP ||
+            sk->sk_protocol == IPPROTO_ICMPV6 ||
             sk->sk_protocol == IPPROTO_RAW)) {
                ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
                                sizeof(struct ipv6hdr));

diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index d5544cf..ff033d1 100644 (file)
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -101,11 +101,21 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
        ipc6.sockc.tsflags = sk->sk_tsflags;
        ipc6.sockc.mark = sk->sk_mark;
 
-       err = sock_cmsg_send(sk, msg, &ipc6.sockc);
-       if (err)
-               return err;
+       if (msg->msg_controllen) {
+               struct ipv6_txoptions opt = {};
+
+               opt.tot_len = sizeof(opt);
+               ipc6.opt = &opt;
 
-       /* TODO: use ip6_datagram_send_ctl to get options from cmsg */
+               err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
+               if (err < 0)
+                       return err;
+
+               /* Changes to txoptions and flow info are not implemented, yet.
+                * Drop the options, fl6 is wiped below.
+                */
+               ipc6.opt = NULL;
+       }
 
        memset(&fl6, 0, sizeof(fl6));
 
@@ -140,7 +150,8 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
        pfh.wcheck = 0;
        pfh.family = AF_INET6;
 
-       ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
+       if (ipc6.hlimit < 0)
+               ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 
        lock_sock(sk);
        err = ip6_append_data(sk, ping_getfrag, &pfh, len,