[PATCH 4/4]: Update API documentation

[Gerrit Renker <gerrit@erg.abdn.ac.uk>]

[DCCP]: Update API documentation 

This adds documentation on the use of service codes on 
client and server.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
---
 Documentation/networking/dccp.txt |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -38,8 +38,10 @@ Socket options
 DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of
 service codes (RFC 4340, sec. 8.1.2); if this socket option is not set,
 the socket will fall back to 0 (which means that no meaningful service code
-is present). Connecting sockets set at most one service option; for
-listening sockets, multiple service codes can be specified.
+is present). On active sockets this is set before connect(); specifying more
+than one code has no effect (all subsequent service codes are ignored). The
+case is different for passive sockets, where multiple service codes (up to 32)
+can be set before calling bind().
 
 DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet
 size (application payload size) in bytes, see RFC 4340, section 14.
@@ -124,5 +126,5 @@ Notes
 == 
 DCCP does not travel through NAT successfully at present on many boxes. This is
-because the checksum covers the psuedo-header as per TCP and UDP. Linux NAT
+because the checksum covers the pseudo-header as per TCP and UDP. Linux NAT
 support for DCCP has been added.