From 7c559a9e44ee61faf2f339604ce708decb345a93 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Thu, 4 Oct 2007 14:39:22 -0700 Subject: [DCCP]: Add socket option to query the current MPS This enables applications to query the current value of the Maximum Packet Size via a socket option, suggested as a SHOULD in (RFC 4340, p. 102). This socket option is useful to avoid the annoying bail-out via `-EMSGSIZE'. In particular, as fragmentation is not currently supported (and its use is partly discouraged in RFC 4340). With this option, it is possible to size buffers accordingly, e.g. int buflen = dccp_get_cur_mps(sockfd); /* or */ if (msgsize > dccp_get_cur_mps(sockfd)) die("message is too large for this path"); Signed-off-by: Gerrit Renker Signed-off-by: Ian McDonald Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- include/linux/dccp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/dccp.h b/include/linux/dccp.h index 4ed82e2c9f65..0e44a3e5208d 100644 --- a/include/linux/dccp.h +++ b/include/linux/dccp.h @@ -202,6 +202,7 @@ struct dccp_so_feat { #define DCCP_SOCKOPT_SERVICE 2 #define DCCP_SOCKOPT_CHANGE_L 3 #define DCCP_SOCKOPT_CHANGE_R 4 +#define DCCP_SOCKOPT_GET_CUR_MPS 5 #define DCCP_SOCKOPT_SEND_CSCOV 10 #define DCCP_SOCKOPT_RECV_CSCOV 11 #define DCCP_SOCKOPT_CCID_RX_INFO 128 -- cgit v1.2.3-59-g8ed1b