Is recv/sendmsg important for AF_INET only sockets?

Hi, I am implementing a small BSD socket layer which supports only the AF_INET family. I am wondering whether recvmsg() and sendmsg() calls are required for the INET protocol family. I don't know if I should implemented it or not. I have looked up some open source projects and grepped for re

Tutorials or notes available for 4.4's ipsec, ipfw, and divert socket?

Hi, I am reading the IP layer source code and I am wondering if there have been mails on this mailing list, or other tutorial documents on the web explaining the design principles  of the implementation of ipfw , ipsec, and divert socket in 4.4 kernel. Please tell me where can I find them if

Does 4.4 FreeBSD kernel supports TCP simultaneous open?

Hi, I am tracing the FreeBSD 4.4 kernel and I found that its TCP seems NOT be able to do simultaneous open according to the source code. In tcp_input.c,  even though code near line #1750,   case TCPS_SYN_RECEIVED:    .   if (tp->t_flags & TF_NEEDFIN) {   tp->t_state = TCPS_FIN_WAIT_1;