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Commit 63b94938 authored by Geir Ola Vaagland's avatar Geir Ola Vaagland Committed by David S. Miller
Browse files

net: sctp: implement rfc6458, 5.3.4. SCTP_SNDINFO cmsg support 



This patch implements section 5.3.4. of RFC6458, that is, support
for 'SCTP Send Information Structure' (SCTP_SNDINFO) which can be
placed into ancillary data cmsghdr structure for sendmsg() calls.

The sctp_sndinfo structure is defined as per RFC as below ...

  struct sctp_sndinfo {
    uint16_t snd_sid;
    uint16_t snd_flags;
    uint32_t snd_ppid;
    uint32_t snd_context;
    sctp_assoc_t snd_assoc_id;
  };

... and supplied under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_SNDINFO, while cmsg_data[] contains struct sctp_sndinfo.
An sctp_sndinfo item always corresponds to the data in msg_iov.

Joint work with Daniel Borkmann.

Signed-off-by: default avatarGeir Ola Vaagland <geirola@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1a98c69a

include/net/sctp/structs.h

+2 −1
Original line number Diff line number Diff line
@@ -1919,7 +1919,8 @@ struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc); 
/* A convenience structure to parse out SCTP specific CMSGs. */

typedef struct sctp_cmsgs {

	struct sctp_initmsg *init;

	struct sctp_sndrcvinfo *info;

	struct sctp_sndrcvinfo *srinfo;

	struct sctp_sndinfo *sinfo;

} sctp_cmsgs_t;



/* Structure for tracking memory objects */

include/uapi/linux/sctp.h

+20 −2
Original line number Diff line number Diff line
@@ -154,6 +154,22 @@ struct sctp_sndrcvinfo { 
	sctp_assoc_t sinfo_assoc_id;

};



/* 5.3.4 SCTP Send Information Structure (SCTP_SNDINFO)

 *

 *   This cmsghdr structure specifies SCTP options for sendmsg().

 *

 *   cmsg_level    cmsg_type      cmsg_data[]

 *   ------------  ------------   -------------------

 *   IPPROTO_SCTP  SCTP_SNDINFO   struct sctp_sndinfo

 */

struct sctp_sndinfo {

	__u16 snd_sid;

	__u16 snd_flags;

	__u32 snd_ppid;

	__u32 snd_context;

	sctp_assoc_t snd_assoc_id;

};



/*

 *  sinfo_flags: 16 bits (unsigned integer)

 *
@@ -181,6 +197,8 @@ typedef enum sctp_cmsg_type { 
#define SCTP_INIT	SCTP_INIT

	SCTP_SNDRCV,		/* 5.2.2 SCTP Header Information Structure */

#define SCTP_SNDRCV	SCTP_SNDRCV

	SCTP_SNDINFO,		/* 5.3.4 SCTP Send Information Structure */

#define SCTP_SNDINFO	SCTP_SNDINFO

} sctp_cmsg_t;



/*

net/sctp/socket.c

+57 −20
Original line number Diff line number Diff line
@@ -1602,12 +1602,13 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk, 
	struct sctp_initmsg *sinit;

	sctp_assoc_t associd = 0;

	sctp_cmsgs_t cmsgs = { NULL };

	int err;

	sctp_scope_t scope;

	long timeo;

	__u16 sinfo_flags = 0;

	bool fill_sinfo_ttl = false;

	struct sctp_datamsg *datamsg;

	int msg_flags = msg->msg_flags;

	__u16 sinfo_flags = 0;

	long timeo;

	int err;



	err = 0;

	sp = sctp_sk(sk);
@@ -1648,10 +1649,21 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk, 
		msg_name = msg->msg_name;

	}



	sinfo = cmsgs.info;

	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;



	/* Did the user specify SNDRCVINFO?  */

		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;
@@ -1858,8 +1870,8 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk, 
	pr_debug("%s: we have a valid association\n", __func__);



	if (!sinfo) {

		/* If the user didn't specify SNDRCVINFO, make up one with

		 * some defaults.

		/* 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;
@@ -1868,7 +1880,13 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk, 
		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;

	}



	/* API 7.1.7, the sndbuf size per association bounds the
@@ -6390,8 +6408,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs) 
	struct cmsghdr *cmsg;

	struct msghdr *my_msg = (struct msghdr *)msg;



	for (cmsg = CMSG_FIRSTHDR(msg);

	     cmsg != NULL;

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;

	     cmsg = CMSG_NXTHDR(my_msg, cmsg)) {

		if (!CMSG_OK(my_msg, cmsg))

			return -EINVAL;
@@ -6404,7 +6421,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs) 
		switch (cmsg->cmsg_type) {

		case SCTP_INIT:

			/* SCTP Socket API Extension

			 * 5.2.1 SCTP Initiation Structure (SCTP_INIT)

			 * 5.3.1 SCTP Initiation Structure (SCTP_INIT)

			 *

			 * This cmsghdr structure provides information for

			 * initializing new SCTP associations with sendmsg().
@@ -6416,15 +6433,15 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs) 
			 * ------------  ------------   ----------------------

			 * IPPROTO_SCTP  SCTP_INIT      struct sctp_initmsg

			 */

			if (cmsg->cmsg_len !=

			    CMSG_LEN(sizeof(struct sctp_initmsg)))

			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct sctp_initmsg)))

				return -EINVAL;

			cmsgs->init = (struct sctp_initmsg *)CMSG_DATA(cmsg);



			cmsgs->init = CMSG_DATA(cmsg);

			break;



		case SCTP_SNDRCV:

			/* SCTP Socket API Extension

			 * 5.2.2 SCTP Header Information Structure(SCTP_SNDRCV)

			 * 5.3.2 SCTP Header Information Structure(SCTP_SNDRCV)

			 *

			 * This cmsghdr structure specifies SCTP options for

			 * sendmsg() and describes SCTP header information
@@ -6434,24 +6451,44 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs) 
			 * ------------  ------------   ----------------------

			 * IPPROTO_SCTP  SCTP_SNDRCV    struct sctp_sndrcvinfo

			 */

			if (cmsg->cmsg_len !=

			    CMSG_LEN(sizeof(struct sctp_sndrcvinfo)))

			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct sctp_sndrcvinfo)))

				return -EINVAL;



			cmsgs->info =

				(struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);

			cmsgs->srinfo = CMSG_DATA(cmsg);



			/* Minimally, validate the sinfo_flags. */

			if (cmsgs->info->sinfo_flags &

			if (cmsgs->srinfo->sinfo_flags &

			    ~(SCTP_UNORDERED | SCTP_ADDR_OVER |

			      SCTP_ABORT | SCTP_EOF))

				return -EINVAL;

			break;



		case SCTP_SNDINFO:

			/* SCTP Socket API Extension

			 * 5.3.4 SCTP Send Information Structure (SCTP_SNDINFO)

			 *

			 * This cmsghdr structure specifies SCTP options for

			 * sendmsg(). This structure and SCTP_RCVINFO replaces

			 * SCTP_SNDRCV which has been deprecated.

			 *

			 * cmsg_level    cmsg_type      cmsg_data[]

			 * ------------  ------------   ---------------------

			 * IPPROTO_SCTP  SCTP_SNDINFO    struct sctp_sndinfo

			 */

			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct sctp_sndinfo)))

				return -EINVAL;



			cmsgs->sinfo = CMSG_DATA(cmsg);



			if (cmsgs->sinfo->snd_flags &

			    ~(SCTP_UNORDERED | SCTP_ADDR_OVER |

			      SCTP_ABORT | SCTP_EOF))

				return -EINVAL;

			break;

		default:

			return -EINVAL;

		}

	}



	return 0;

}