sctp: factor out sctp_sendmsg_parse from sctp_sendmsg

This patch is to move the codes for parsing msghdr and checking
sk into sctp_sendmsg_parse.

Note that different from before, 'sinfo' in sctp_sendmsg won't
be NULL any more. It gets the value either from cmsgs->srinfo,
cmsgs->sinfo or asoc. With it, the 'sinfo' and 'fill_sinfo_ttl'
check can be removed from sctp_sendmsg.

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

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 68691d2b31679a0b6ce194dae7941e2d714660f3..bf089e59c79261d9bb2354a3b2883a7717a69fab 100644 (file)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1606,6 +1606,61 @@ static int sctp_error(struct sock *sk, int flags, int err)
 static int sctp_msghdr_parse(const struct msghdr *msg,
                             struct sctp_cmsgs *cmsgs);
 
+static int sctp_sendmsg_parse(struct sock *sk, struct sctp_cmsgs *cmsgs,
+                             struct sctp_sndrcvinfo *srinfo,
+                             const struct msghdr *msg, size_t msg_len)
+{
+       __u16 sflags;
+       int err;
+
+       if (sctp_sstate(sk, LISTENING) && sctp_style(sk, TCP))
+               return -EPIPE;
+
+       if (msg_len > sk->sk_sndbuf)
+               return -EMSGSIZE;
+
+       memset(cmsgs, 0, sizeof(*cmsgs));
+       err = sctp_msghdr_parse(msg, cmsgs);
+       if (err) {
+               pr_debug("%s: msghdr parse err:%x\n", __func__, err);
+               return err;
+       }
+
+       memset(srinfo, 0, sizeof(*srinfo));
+       if (cmsgs->srinfo) {
+               srinfo->sinfo_stream = cmsgs->srinfo->sinfo_stream;
+               srinfo->sinfo_flags = cmsgs->srinfo->sinfo_flags;
+               srinfo->sinfo_ppid = cmsgs->srinfo->sinfo_ppid;
+               srinfo->sinfo_context = cmsgs->srinfo->sinfo_context;
+               srinfo->sinfo_assoc_id = cmsgs->srinfo->sinfo_assoc_id;
+               srinfo->sinfo_timetolive = cmsgs->srinfo->sinfo_timetolive;
+       }
+
+       if (cmsgs->sinfo) {
+               srinfo->sinfo_stream = cmsgs->sinfo->snd_sid;
+               srinfo->sinfo_flags = cmsgs->sinfo->snd_flags;
+               srinfo->sinfo_ppid = cmsgs->sinfo->snd_ppid;
+               srinfo->sinfo_context = cmsgs->sinfo->snd_context;
+               srinfo->sinfo_assoc_id = cmsgs->sinfo->snd_assoc_id;
+       }
+
+       sflags = srinfo->sinfo_flags;
+       if (!sflags && msg_len)
+               return 0;
+
+       if (sctp_style(sk, TCP) && (sflags & (SCTP_EOF | SCTP_ABORT)))
+               return -EINVAL;
+
+       if (((sflags & SCTP_EOF) && msg_len > 0) ||
+           (!(sflags & (SCTP_EOF | SCTP_ABORT)) && msg_len == 0))
+               return -EINVAL;
+
+       if ((sflags & SCTP_ADDR_OVER) && !msg->msg_name)
+               return -EINVAL;
+
+       return 0;
+}
+
 static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
                                 struct sctp_cmsgs *cmsgs,
                                 union sctp_addr *daddr,
@@ -1839,39 +1894,23 @@ static union sctp_addr *sctp_sendmsg_get_daddr(struct sock *sk,
 
 static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 {
-       struct sctp_sock *sp;
-       struct sctp_endpoint *ep;
+       struct sctp_endpoint *ep = sctp_sk(sk)->ep;
        struct sctp_association *new_asoc = NULL, *asoc = NULL;
        struct sctp_transport *transport, *chunk_tp;
-       struct sctp_sndrcvinfo default_sinfo;
-       struct sctp_sndrcvinfo *sinfo;
-       struct sctp_initmsg *sinit;
+       struct sctp_sndrcvinfo _sinfo, *sinfo;
        sctp_assoc_t associd = 0;
        struct sctp_cmsgs cmsgs = { NULL };
-       bool fill_sinfo_ttl = false;
        __u16 sinfo_flags = 0;
        union sctp_addr *daddr;
        int err;
 
-       err = 0;
-       sp = sctp_sk(sk);
-       ep = sp->ep;
-
-       pr_debug("%s: sk:%p, msg:%p, msg_len:%zu ep:%p\n", __func__, sk,
-                msg, msg_len, ep);
-
-       /* We cannot send a message over a TCP-style listening socket. */
-       if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) {
-               err = -EPIPE;
+       /* Parse and get snd_info */
+       err = sctp_sendmsg_parse(sk, &cmsgs, &_sinfo, msg, msg_len);
+       if (err)
                goto out_nounlock;
-       }
 
-       /* Parse out the SCTP CMSGs.  */
-       err = sctp_msghdr_parse(msg, &cmsgs);
-       if (err) {
-               pr_debug("%s: msghdr parse err:%x\n", __func__, err);
-               goto out_nounlock;
-       }
+       sinfo  = &_sinfo;
+       sinfo_flags = sinfo->sinfo_flags;
 
        /* Get daddr from msg */
        daddr = sctp_sendmsg_get_daddr(sk, msg, &cmsgs);
@@ -1880,58 +1919,6 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
                goto out_nounlock;
        }
 
-       sinit = cmsgs.init;
-       if (cmsgs.sinfo != NULL) {
-               memset(&default_sinfo, 0, sizeof(default_sinfo));
-               default_sinfo.sinfo_stream = cmsgs.sinfo->snd_sid;
-               default_sinfo.sinfo_flags = cmsgs.sinfo->snd_flags;
-               default_sinfo.sinfo_ppid = cmsgs.sinfo->snd_ppid;
-               default_sinfo.sinfo_context = cmsgs.sinfo->snd_context;
-               default_sinfo.sinfo_assoc_id = cmsgs.sinfo->snd_assoc_id;
-
-               sinfo = &default_sinfo;
-               fill_sinfo_ttl = true;
-       } else {
-               sinfo = cmsgs.srinfo;
-       }
-       /* Did the user specify SNDINFO/SNDRCVINFO? */
-       if (sinfo) {
-               sinfo_flags = sinfo->sinfo_flags;
-               associd = sinfo->sinfo_assoc_id;
-       }
-
-       pr_debug("%s: msg_len:%zu, sinfo_flags:0x%x\n", __func__,
-                msg_len, sinfo_flags);
-
-       /* SCTP_EOF or SCTP_ABORT cannot be set on a TCP-style socket. */
-       if (sctp_style(sk, TCP) && (sinfo_flags & (SCTP_EOF | SCTP_ABORT))) {
-               err = -EINVAL;
-               goto out_nounlock;
-       }
-
-       /* If SCTP_EOF is set, no data can be sent. Disallow sending zero
-        * length messages when SCTP_EOF|SCTP_ABORT is not set.
-        * If SCTP_ABORT is set, the message length could be non zero with
-        * the msg_iov set to the user abort reason.
-        */
-       if (((sinfo_flags & SCTP_EOF) && (msg_len > 0)) ||
-           (!(sinfo_flags & (SCTP_EOF|SCTP_ABORT)) && (msg_len == 0))) {
-               err = -EINVAL;
-               goto out_nounlock;
-       }
-
-       /* If SCTP_ADDR_OVER is set, there must be an address
-        * specified in msg_name.
-        */
-       if ((sinfo_flags & SCTP_ADDR_OVER) && (!msg->msg_name)) {
-               err = -EINVAL;
-               goto out_nounlock;
-       }
-
-       transport = NULL;
-
-       pr_debug("%s: about to look up association\n", __func__);
-
        lock_sock(sk);
 
        /* If a msg_name has been specified, assume this is to be used.  */
@@ -1964,36 +1951,15 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
                new_asoc = asoc;
        }
 
-       /* ASSERT: we have a valid association at this point.  */
-       pr_debug("%s: we have a valid association\n", __func__);
-
-       if (!sinfo) {
-               /* If the user didn't specify SNDINFO/SNDRCVINFO, make up
-                * one with some defaults.
-                */
-               memset(&default_sinfo, 0, sizeof(default_sinfo));
-               default_sinfo.sinfo_stream = asoc->default_stream;
-               default_sinfo.sinfo_flags = asoc->default_flags;
-               default_sinfo.sinfo_ppid = asoc->default_ppid;
-               default_sinfo.sinfo_context = asoc->default_context;
-               default_sinfo.sinfo_timetolive = asoc->default_timetolive;
-               default_sinfo.sinfo_assoc_id = sctp_assoc2id(asoc);
-
-               sinfo = &default_sinfo;
-       } else if (fill_sinfo_ttl) {
-               /* In case SNDINFO was specified, we still need to fill
-                * it with a default ttl from the assoc here.
-                */
-               sinfo->sinfo_timetolive = asoc->default_timetolive;
+       if (!cmsgs.srinfo && !cmsgs.sinfo) {
+               sinfo->sinfo_stream = asoc->default_stream;
+               sinfo->sinfo_ppid = asoc->default_ppid;
+               sinfo->sinfo_context = asoc->default_context;
+               sinfo->sinfo_assoc_id = sctp_assoc2id(asoc);
        }
 
-       /* API 7.1.7, the sndbuf size per association bounds the
-        * maximum size of data that can be sent in a single send call.
-        */
-       if (msg_len > sk->sk_sndbuf) {
-               err = -EMSGSIZE;
-               goto out_free;
-       }
+       if (!cmsgs.srinfo)
+               sinfo->sinfo_timetolive = asoc->default_timetolive;
 
        /* If an address is passed with the sendto/sendmsg call, it is used
         * to override the primary destination address in the TCP model, or