sctp: add support for setting flowlabel when adding a transport

Struct sockaddr_in6 has the member sin6_flowinfo that includes the
ipv6 flowlabel, it should also support for setting flowlabel when
adding a transport whose ipaddr is from userspace.

Note that addrinfo in sctp_sendmsg is using struct in6_addr for
the secondary addrs, which doesn't contain sin6_flowinfo, and
it needs to copy sin6_flowinfo from the primary addr.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 50b7ef975b42..502c0d7cb105 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1697,6 +1697,7 @@ static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
         struct sctp_association *asoc;
         enum sctp_scope scope;
         struct cmsghdr *cmsg;
+        __be32 flowinfo = 0;
         struct sctp_af *af;
         int err;
 
@@ -1781,6 +1782,9 @@ static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
         if (!cmsgs->addrs_msg)
                 return 0;
 
+        if (daddr->sa.sa_family == AF_INET6)
+                flowinfo = daddr->v6.sin6_flowinfo;
+
         /* sendv addr list parse */
         for_each_cmsghdr(cmsg, cmsgs->addrs_msg) {
                 struct sctp_transport *transport;
@@ -1813,6 +1817,7 @@ static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
                         }
 
                         dlen = sizeof(struct in6_addr);
+                        daddr->v6.sin6_flowinfo = flowinfo;
                         daddr->v6.sin6_family = AF_INET6;
                         daddr->v6.sin6_port = htons(asoc->peer.port);
                         memcpy(&daddr->v6.sin6_addr, CMSG_DATA(cmsg), dlen);