diff -ur man-pages-3.43.orig/man7/tcp.7 man-pages-3.43/man7/tcp.7
--- man-pages-3.43.orig/man7/tcp.7	2012-10-15 11:13:50.000000000 +0200
+++ man-pages-3.43/man7/tcp.7	2012-10-25 19:37:24.084706083 +0200
@@ -820,7 +820,58 @@
 socket options are valid on TCP sockets.
 For more information see
 .BR ip (7).
-.\" FIXME Document TCP_CONGESTION (new in 2.6.13)
+.TP
+.BR TCP_CONGESTION " (since Linux 2.6.13)"
+Get or set the congestion-control algorithm for this socket.
+The
+.I optval
+argument is a pointer to a character-string buffer.
+
+For
+.BR getsockopt ()
+.I *optlen
+specifies the amount of space available in the buffer pointed to by
+.IR optval ,
+which should be at least 16 bytes (defined by the kernel-internal constant
+.BR TCP_CA_NAME_MAX ).
+On return, the buffer pointed to by
+.I optval
+is set to a null-terminated string containing the name of the
+congestion-control algorithm for this socket, and
+.I *optlen
+is set to the minimum of its original value and
+.BR TCP_CA_NAME_MAX .
+If the value passed in
+.I *optlen
+is too small, then the string returned in
+.I *optval
+is silently truncated, and no terminating null byte is added.
+If an empty string is returned, then the socket is using the default
+congestion-control algorithm, determined as described under
+.I tcp_congestion_control
+above.
+
+For
+.BR setsockopt ()
+.I optlen
+specifies the length of the congestion-control algorithm name
+contained in the buffer pointed to by
+.IR optval ;
+this length need not include any terminating null byte.
+The algorithm "reno" is always permitted;
+other algorithms may be available, depending on kernel configuration.
+Possible errors from
+.BR setsockopt ()
+include:
+algorithm not found/available
+.RB ( ENOENT );
+setting this algorithm requires the
+.B CAP_NET_ADMIN
+capability
+.RB ( EPERM );
+and failure getting kernel module
+.RB ( EBUSY ).
+.I
 .TP
 .BR TCP_CORK " (since Linux 2.2)"
 .\" precisely: since 2.1.127