On Mon, Mar 05, 2018 at 08:44:19PM +0800, Xin Long wrote:
> 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: Xin Long <lucien....@gmail.com>
> ---
> include/net/sctp/structs.h | 1 +
> include/uapi/linux/sctp.h | 6 ++++
> net/sctp/socket.c | 77
> ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 84 insertions(+)
>
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index d40a2a3..ec6e46b 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -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 */
> diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
> index 0dd1f82..a1bc350 100644
> --- a/include/uapi/linux/sctp.h
> +++ b/include/uapi/linux/sctp.h
> @@ -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;
>
> /*
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index fdde697..067b57a 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -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;
I think this is being handled differently from what the RFC specifies.
AFAIU the rfc defines these two options being each one an array of a
specific element type, in_addr and in6_addr.
The patch is saving both options into a single pointer, which later is
processed as a list of (in_addr or in6_addr) elements.
If an application specifies both options, each with a list of its own
addresses, it will ignore one of the options.
> + break;
> default:
> return -EINVAL;
> }
> --
> 2.1.0
>
