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Commit 2c0dbaa0 authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: add support for SCTP_DSTADDRV4/6 Information for sendmsg 



This patch is to add support for Destination IPv4/6 Address options
for sendmsg, as described in section 5.3.9/10 of RFC6458.

With this option, you can provide more than one destination addrs
to sendmsg when creating asoc, like sctp_connectx.

It's also a necessary send info for sctp_sendv.

Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ed63afb8

include/net/sctp/structs.h

+1 −0
Original line number Diff line number Diff line
@@ -2113,6 +2113,7 @@ struct sctp_cmsgs { 
	struct sctp_sndrcvinfo *srinfo;

	struct sctp_sndinfo *sinfo;

	struct sctp_prinfo *prinfo;

	struct msghdr *addrs_msg;

};



/* Structure for tracking memory objects */

include/uapi/linux/sctp.h

+6 −0
Original line number Diff line number Diff line
@@ -308,6 +308,12 @@ typedef enum sctp_cmsg_type { 
#define SCTP_NXTINFO	SCTP_NXTINFO

	SCTP_PRINFO,		/* 5.3.7 SCTP PR-SCTP Information Structure */

#define SCTP_PRINFO	SCTP_PRINFO

	SCTP_AUTHINFO,		/* 5.3.8 SCTP AUTH Information Structure (RESERVED) */

#define SCTP_AUTHINFO	SCTP_AUTHINFO

	SCTP_DSTADDRV4,		/* 5.3.9 SCTP Destination IPv4 Address Structure */

#define SCTP_DSTADDRV4	SCTP_DSTADDRV4

	SCTP_DSTADDRV6,		/* 5.3.10 SCTP Destination IPv6 Address Structure */

#define SCTP_DSTADDRV6	SCTP_DSTADDRV6

} sctp_cmsg_t;



/*

net/sctp/socket.c

+77 −0
Original line number Diff line number Diff line
@@ -1676,6 +1676,7 @@ static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags, 
	struct net *net = sock_net(sk);

	struct sctp_association *asoc;

	enum sctp_scope scope;

	struct cmsghdr *cmsg;

	int err = -EINVAL;



	*tp = NULL;
@@ -1741,6 +1742,67 @@ static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags, 
		goto free;

	}



	if (!cmsgs->addrs_msg)

		return 0;



	/* sendv addr list parse */

	for_each_cmsghdr(cmsg, cmsgs->addrs_msg) {

		struct sctp_transport *transport;

		struct sctp_association *old;

		union sctp_addr _daddr;

		int dlen;



		if (cmsg->cmsg_level != IPPROTO_SCTP ||

		    (cmsg->cmsg_type != SCTP_DSTADDRV4 &&

		     cmsg->cmsg_type != SCTP_DSTADDRV6))

			continue;



		daddr = &_daddr;

		memset(daddr, 0, sizeof(*daddr));

		dlen = cmsg->cmsg_len - sizeof(struct cmsghdr);

		if (cmsg->cmsg_type == SCTP_DSTADDRV4) {

			if (dlen < sizeof(struct in_addr))

				goto free;



			dlen = sizeof(struct in_addr);

			daddr->v4.sin_family = AF_INET;

			daddr->v4.sin_port = htons(asoc->peer.port);

			memcpy(&daddr->v4.sin_addr, CMSG_DATA(cmsg), dlen);

		} else {

			if (dlen < sizeof(struct in6_addr))

				goto free;



			dlen = sizeof(struct in6_addr);

			daddr->v6.sin6_family = AF_INET6;

			daddr->v6.sin6_port = htons(asoc->peer.port);

			memcpy(&daddr->v6.sin6_addr, CMSG_DATA(cmsg), dlen);

		}

		err = sctp_verify_addr(sk, daddr, sizeof(*daddr));

		if (err)

			goto free;



		old = sctp_endpoint_lookup_assoc(ep, daddr, &transport);

		if (old && old != asoc) {

			if (old->state >= SCTP_STATE_ESTABLISHED)

				err = -EISCONN;

			else

				err = -EALREADY;

			goto free;

		}



		if (sctp_endpoint_is_peeled_off(ep, daddr)) {

			err = -EADDRNOTAVAIL;

			goto free;

		}



		transport = sctp_assoc_add_peer(asoc, daddr, GFP_KERNEL,

						SCTP_UNKNOWN);

		if (!transport) {

			err = -ENOMEM;

			goto free;

		}

	}



	return 0;



free:
@@ -7778,6 +7840,21 @@ static int sctp_msghdr_parse(const struct msghdr *msg, struct sctp_cmsgs *cmsgs) 
			if (cmsgs->prinfo->pr_policy == SCTP_PR_SCTP_NONE)

				cmsgs->prinfo->pr_value = 0;

			break;

		case SCTP_DSTADDRV4:

		case SCTP_DSTADDRV6:

			/* SCTP Socket API Extension

			 * 5.3.9/10 SCTP Destination IPv4/6 Address Structure (SCTP_DSTADDRV4/6)

			 *

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

			 *

			 * cmsg_level    cmsg_type         cmsg_data[]

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

			 * IPPROTO_SCTP  SCTP_DSTADDRV4 struct in_addr

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

			 * IPPROTO_SCTP  SCTP_DSTADDRV6 struct in6_addr

			 */

			cmsgs->addrs_msg = my_msg;

			break;

		default:

			return -EINVAL;

		}