/* if_loop.c 4.16 83/02/11 */ /* * Loopback interface driver for protocol testing and timing. */ #include "../h/param.h" #include "../h/systm.h" #include "../h/mbuf.h" #include "../h/socket.h" #include "../h/errno.h" #include "../net/if.h" #include "../net/netisr.h" #include "../net/route.h" #include "../netinet/in.h" #include "../netinet/in_systm.h" #include "../netinet/ip.h" #include "../netinet/ip_var.h" #include "../machine/mtpr.h" #define LONET 127 #define LOMTU (1024+512) struct ifnet loif; int looutput(); loattach() { register struct ifnet *ifp = &loif; register struct sockaddr_in *sin; ifp->if_name = "lo"; ifp->if_mtu = LOMTU; ifp->if_net = LONET; sin = (struct sockaddr_in *)&ifp->if_addr; sin->sin_family = AF_INET; sin->sin_addr = if_makeaddr(ifp->if_net, 0); ifp->if_flags = IFF_UP; ifp->if_output = looutput; if_attach(ifp); if_rtinit(ifp, RTF_UP); } looutput(ifp, m0, dst) struct ifnet *ifp; struct mbuf *m0; struct sockaddr *dst; { int s = splimp(); register struct ifqueue *ifq; ifp->if_opackets++; switch (dst->sa_family) { #ifdef INET case AF_INET: ifq = &ipintrq; if (IF_QFULL(ifq)) { IF_DROP(ifq); m_freem(m0); splx(s); return (ENOBUFS); } IF_ENQUEUE(ifq, m0); schednetisr(NETISR_IP); break; #endif default: splx(s); printf("lo%d: can't handle af%d\n", ifp->if_unit, dst->sa_family); m_freem(m0); return (EAFNOSUPPORT); } ifp->if_ipackets++; splx(s); return (0); }