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| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2007-10-04 14:39:22 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-10-10 16:54:31 -0700 |
| commit | 7c559a9e44ee61faf2f339604ce708decb345a93 (patch) | |
| tree | 8e0e89521445a42cf801747af20be172b6e9e582 /include/linux/dccp.h | |
| parent | bc8498721dfe3f7d537f4f75302be7dbe9c7b939 (diff) | |
| download | lwn-7c559a9e44ee61faf2f339604ce708decb345a93.tar.gz lwn-7c559a9e44ee61faf2f339604ce708decb345a93.zip | |
[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 <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/dccp.h')
| -rw-r--r-- | include/linux/dccp.h | 1 |
1 files changed, 1 insertions, 0 deletions
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 |