Re: [PATCH net-next 1/3] sctp: add support for PR-SCTP Information for sendmsg

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Mon, Mar 05, 2018 at 08:44:18PM +0800, Xin Long wrote:
> This patch is to add support for PR-SCTP Information for sendmsg,
> as described in section 5.3.7 of RFC6458.
> 
> With this option, you can specify pr_policy and pr_value for user
> data in sendmsg.
> 
> It's also a necessary send info for sctp_sendv.
> 
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
>  include/net/sctp/structs.h |  1 +
>  include/uapi/linux/sctp.h  | 15 +++++++++++++++
>  net/sctp/socket.c          | 31 ++++++++++++++++++++++++++++++-
>  3 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index 03e92dd..d40a2a3 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -2112,6 +2112,7 @@ struct sctp_cmsgs {
>  	struct sctp_initmsg *init;
>  	struct sctp_sndrcvinfo *srinfo;
>  	struct sctp_sndinfo *sinfo;
> +	struct sctp_prinfo *prinfo;
>  };
>  
>  /* Structure for tracking memory objects */
> diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
> index 4c4db14..0dd1f82 100644
> --- a/include/uapi/linux/sctp.h
> +++ b/include/uapi/linux/sctp.h
> @@ -260,6 +260,19 @@ struct sctp_nxtinfo {
>  	sctp_assoc_t nxt_assoc_id;
>  };
>  
> +/* 5.3.7 SCTP PR-SCTP Information Structure (SCTP_PRINFO)
> + *
> + *   This cmsghdr structure specifies SCTP options for sendmsg().
> + *
> + *   cmsg_level    cmsg_type      cmsg_data[]
> + *   ------------  ------------   -------------------
> + *   IPPROTO_SCTP  SCTP_PRINFO    struct sctp_prinfo
> + */
> +struct sctp_prinfo {
> +	__u16 pr_policy;
> +	__u32 pr_value;
> +};
> +
>  /*
>   *  sinfo_flags: 16 bits (unsigned integer)
>   *
> @@ -293,6 +306,8 @@ typedef enum sctp_cmsg_type {
>  #define SCTP_RCVINFO	SCTP_RCVINFO
>  	SCTP_NXTINFO,		/* 5.3.6 SCTP Next Receive Information Structure */
>  #define SCTP_NXTINFO	SCTP_NXTINFO
> +	SCTP_PRINFO,		/* 5.3.7 SCTP PR-SCTP Information Structure */
> +#define SCTP_PRINFO	SCTP_PRINFO
>  } sctp_cmsg_t;
>  
>  /*
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 7fa7603..fdde697 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -1644,6 +1644,12 @@ static int sctp_sendmsg_parse(struct sock *sk, struct sctp_cmsgs *cmsgs,
>  		srinfo->sinfo_assoc_id = cmsgs->sinfo->snd_assoc_id;
>  	}
>  
> +	if (cmsgs->prinfo) {
> +		srinfo->sinfo_timetolive = cmsgs->prinfo->pr_value;
> +		SCTP_PR_SET_POLICY(srinfo->sinfo_flags,
> +				   cmsgs->prinfo->pr_policy);
> +	}
> +
>  	sflags = srinfo->sinfo_flags;
>  	if (!sflags && msg_len)
>  		return 0;
> @@ -1901,9 +1907,12 @@ static void sctp_sendmsg_update_sinfo(struct sctp_association *asoc,
>  		sinfo->sinfo_ppid = asoc->default_ppid;
>  		sinfo->sinfo_context = asoc->default_context;
>  		sinfo->sinfo_assoc_id = sctp_assoc2id(asoc);
> +
> +		if (!cmsgs->prinfo)
> +			sinfo->sinfo_flags = asoc->default_flags;
>  	}
>  
> -	if (!cmsgs->srinfo)
> +	if (!cmsgs->srinfo && !cmsgs->prinfo)
>  		sinfo->sinfo_timetolive = asoc->default_timetolive;
>  }
>  
> @@ -7749,6 +7758,26 @@ static int sctp_msghdr_parse(const struct msghdr *msg, struct sctp_cmsgs *cmsgs)
>  			      SCTP_ABORT | SCTP_EOF))
>  				return -EINVAL;
>  			break;
> +		case SCTP_PRINFO:
> +			/* SCTP Socket API Extension
> +			 * 5.3.7 SCTP PR-SCTP Information Structure (SCTP_PRINFO)
> +			 *
> +			 * This cmsghdr structure specifies SCTP options for sendmsg().
> +			 *
> +			 * cmsg_level    cmsg_type      cmsg_data[]
> +			 * ------------  ------------   ---------------------
> +			 * IPPROTO_SCTP  SCTP_PRINFO    struct sctp_prinfo
> +			 */
> +			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct sctp_prinfo)))
> +				return -EINVAL;
> +
> +			cmsgs->prinfo = CMSG_DATA(cmsg);
> +			if (cmsgs->prinfo->pr_policy & ~SCTP_PR_SCTP_MASK)
> +				return -EINVAL;
> +
> +			if (cmsgs->prinfo->pr_policy = SCTP_PR_SCTP_NONE)
> +				cmsgs->prinfo->pr_value = 0;
> +			break;
>  		default:
>  			return -EINVAL;
>  		}
> -- 
> 2.1.0
>