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sctp: factor out sctp_sendmsg_parse from sctp_sendmsg
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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>
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Xin Long authored and David S. Miller committed Mar 4, 2018
1 parent becef9b commit 204f817
Showing 1 changed file with 69 additions and 103 deletions.
172 changes: 69 additions & 103 deletions net/sctp/socket.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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);
Expand All @@ -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. */
Expand Down Expand Up @@ -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
Expand Down

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