/* $OpenBSD: if_x25subr.c,v 1.6 2001/05/27 12:19:04 angelos Exp $ */ /* $NetBSD: if_x25subr.c,v 1.13 1996/05/09 22:29:25 scottr Exp $ */ /* * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)if_x25subr.c 8.1 (Berkeley) 6/10/93 */ #include #include #include #include #include #include #include #include #include #include #include /* XXX for setsoftnet(). This must die. */ #include #include #include #include #include #include #include #include #include #ifdef INET #include #include #else #ifdef _KERNEL #error options CCITT assumes options INET #endif #endif #ifdef NS #include #include #endif #ifdef ISO #include #include #include #ifdef TPCONS #include #include #endif #endif LIST_HEAD(, llinfo_x25) llinfo_x25; #ifndef _offsetof #define _offsetof(t, m) ((int)((caddr_t)&((t *)0)->m)) #endif struct sockaddr *x25_dgram_sockmask; struct sockaddr_x25 x25_dgmask = { _offsetof(struct sockaddr_x25, x25_udata[1]), /* _len */ 0, /* _family */ 0, /* _net */ {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}, /* _addr */ {0}, /* opts */ -1, /* _udlen */ {-1} /* _udata */ }; struct if_x25stats { int ifx_wrongplen; int ifx_nophdr; } if_x25stats; int x25_autoconnect = 0; #define senderr(x) {error = x; goto bad;} static struct llinfo_x25 *x25_lxalloc __P((struct rtentry *)); /* * Ancillary routines */ static struct llinfo_x25 * x25_lxalloc(rt) register struct rtentry *rt; { register struct llinfo_x25 *lx; register struct sockaddr *dst = rt_key(rt); register struct ifaddr *ifa; MALLOC(lx, struct llinfo_x25 *, sizeof(*lx), M_PCB, M_NOWAIT); if (lx == 0) return lx; Bzero(lx, sizeof(*lx)); lx->lx_rt = rt; lx->lx_family = dst->sa_family; rt->rt_refcnt++; if (rt->rt_llinfo) { LIST_INSERT_AFTER( (struct llinfo_x25 *) rt->rt_llinfo, lx, lx_list); } else { rt->rt_llinfo = (caddr_t) lx; LIST_INSERT_HEAD(&llinfo_x25, lx, lx_list); } for (ifa = rt->rt_ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next) { if (ifa->ifa_addr->sa_family == AF_CCITT) lx->lx_ia = (struct x25_ifaddr *) ifa; } return lx; } void x25_lxfree(lx) register struct llinfo_x25 *lx; { register struct rtentry *rt = lx->lx_rt; register struct pklcd *lcp = lx->lx_lcd; if (lcp) { lcp->lcd_upper = 0; pk_disconnect(lcp); } if ((rt->rt_llinfo == (caddr_t) lx) && (lx->lx_list.le_next->lx_rt == rt)) rt->rt_llinfo = (caddr_t) lx->lx_list.le_next; else rt->rt_llinfo = 0; RTFREE(rt); LIST_REMOVE(lx, lx_list); FREE(lx, M_PCB); } /* * Process a x25 packet as datagram; */ int x25_ifinput(m, v) register struct mbuf *m; void *v; { struct pklcd *lcp = v; struct llinfo_x25 *lx = (struct llinfo_x25 *) lcp->lcd_upnext; register struct ifnet *ifp; struct ifqueue *inq; extern struct timeval time; int s, isr; if (m == 0 || lcp->lcd_state != DATA_TRANSFER) return x25_connect_callback(NULL, lcp); pk_flowcontrol(lcp, 0, 1); /* Generate RR */ ifp = m->m_pkthdr.rcvif; ifp->if_lastchange = time; switch (m->m_type) { default: if (m) m_freem(m); return 0; case MT_DATA: /* FALLTHROUGH */ ; } switch (lx->lx_family) { #ifdef INET case AF_INET: isr = NETISR_IP; inq = &ipintrq; break; #endif #ifdef NS case AF_NS: isr = NETISR_NS; inq = &nsintrq; break; #endif #ifdef ISO case AF_ISO: isr = NETISR_ISO; inq = &clnlintrq; break; #endif default: m_freem(m); ifp->if_noproto++; return 0; } s = splimp(); schednetisr(isr); if (IF_QFULL(inq)) { IF_DROP(inq); m_freem(m); } else { IF_ENQUEUE(inq, m); ifp->if_ibytes += m->m_pkthdr.len; } splx(s); return 0; } int x25_connect_callback(m, v) register struct mbuf *m; void *v; { register struct pklcd *lcp = v; register struct llinfo_x25 *lx = (struct llinfo_x25 *) lcp->lcd_upnext; int do_clear = 1; if (m == 0) goto refused; if (m->m_type != MT_CONTROL) { printf("x25_connect_callback: should panic\n"); goto refused; } switch (pk_decode(mtod(m, struct x25_packet *))) { case PK_CALL_ACCEPTED: lcp->lcd_upper = x25_ifinput; if (lcp->lcd_sb.sb_mb) lcp->lcd_send(lcp); /* XXX start queued packets */ return 0; default: do_clear = 0; refused: lcp->lcd_upper = 0; lx->lx_lcd = 0; if (do_clear) pk_disconnect(lcp); return 0; } } #define SA(p) ((struct sockaddr *)(p)) #define RT(p) ((struct rtentry *)(p)) int x25_dgram_incoming(m0, v) struct mbuf *m0; void *v; { register struct pklcd *lcp = v; register struct rtentry *rt, *nrt; register struct mbuf *m = m0->m_next; /* m0 has calling * sockaddr_x25 */ rt = rtalloc1(SA(&lcp->lcd_faddr), 0); if (rt == 0) { refuse: lcp->lcd_upper = 0; pk_close(lcp); return 0; } rt->rt_refcnt--; if ((nrt = RT(rt->rt_llinfo)) == 0 || rt_mask(rt) != x25_dgram_sockmask) goto refuse; if ((nrt->rt_flags & RTF_UP) == 0) { rt->rt_llinfo = (caddr_t) rtalloc1(rt->rt_gateway, 0); rtfree(nrt); if ((nrt = RT(rt->rt_llinfo)) == 0) goto refuse; nrt->rt_refcnt--; } if (nrt->rt_ifa == 0 || nrt->rt_ifa->ifa_rtrequest != x25_rtrequest) goto refuse; lcp->lcd_send(lcp); /* confirm call */ x25_rtattach(lcp, nrt); m_freem(m); return 0; } /* * X.25 output routine. */ int x25_ifoutput(ifp, m0, dst, rt) struct ifnet *ifp; struct mbuf *m0; struct sockaddr *dst; register struct rtentry *rt; { register struct mbuf *m = m0; register struct llinfo_x25 *lx; struct pklcd *lcp; int error = 0; int plen; for (plen = 0; m; m = m->m_next) plen += m->m_len; m = m0; if ((ifp->if_flags & IFF_UP) == 0) senderr(ENETDOWN); while (rt == 0 || (rt->rt_flags & RTF_GATEWAY)) { if (rt) { if (rt->rt_llinfo) { rt = (struct rtentry *) rt->rt_llinfo; continue; } dst = rt->rt_gateway; } if ((rt = rtalloc1(dst, 1)) == 0) senderr(EHOSTUNREACH); rt->rt_refcnt--; } /* * Sanity checks. */ if ((rt->rt_ifp != ifp) || (rt->rt_flags & (RTF_CLONING | RTF_GATEWAY)) || ((lx = (struct llinfo_x25 *) rt->rt_llinfo) == 0)) { senderr(ENETUNREACH); } if ((m->m_flags & M_PKTHDR) == 0) { if_x25stats.ifx_nophdr++; m = m_gethdr(M_NOWAIT, MT_HEADER); if (m == 0) senderr(ENOBUFS); M_COPY_HDR(m, m0); m_tag_init(m0); m0->m_flags &= ~M_PKTHDR; m->m_pkthdr.len = plen; m->m_next = m0; } if (plen != m->m_pkthdr.len) { if_x25stats.ifx_wrongplen++; m->m_pkthdr.len = plen; } next_circuit: lcp = lx->lx_lcd; if (lcp == 0) { lx->lx_lcd = lcp = pk_attach((struct socket *) 0); if (lcp == 0) senderr(ENOBUFS); lcp->lcd_upper = x25_connect_callback; lcp->lcd_upnext = (caddr_t) lx; lcp->lcd_packetsize = lx->lx_ia->ia_xc.xc_psize; lcp->lcd_flags = X25_MBS_HOLD; } switch (lcp->lcd_state) { case READY: if (dst->sa_family == AF_INET && ifp->if_type == IFT_X25DDN && rt->rt_gateway->sa_family != AF_CCITT) x25_ddnip_to_ccitt(dst, rt); if (rt->rt_gateway->sa_family != AF_CCITT) { if ((rt->rt_flags & RTF_XRESOLVE) == 0) senderr(EHOSTUNREACH); } else if (x25_autoconnect) error = pk_connect(lcp, (struct sockaddr_x25 *) rt->rt_gateway); if (error) senderr(error); /* FALLTHROUGH */ case SENT_CALL: case DATA_TRANSFER: if (sbspace(&lcp->lcd_sb) < 0) { lx = lx->lx_list.le_next; if (lx->lx_rt != rt) senderr(ENOSPC); goto next_circuit; } if (lx->lx_ia) lcp->lcd_dg_timer = lx->lx_ia->ia_xc.xc_dg_idletimo; pk_send(m, lcp); break; default: /* * We count on the timer routine to close idle * connections, if there are not enough circuits to go * around. * * So throw away data for now. * After we get it all working, we'll rewrite to handle * actively closing connections (other than by timers), * when circuits get tight. * * In the DDN case, the imp itself closes connections * under heavy load. */ error = ENOBUFS; bad: if (m) m_freem(m); } return (error); } /* * Simpleminded timer routine. */ void x25_iftimeout(ifp) struct ifnet *ifp; { register struct pkcb *pkcb = 0; register struct pklcd **lcpp, *lcp; int s = splimp(); FOR_ALL_PKCBS(pkcb) if (pkcb->pk_ia->ia_ifp == ifp) for (lcpp = pkcb->pk_chan + pkcb->pk_maxlcn; --lcpp > pkcb->pk_chan;) if ((lcp = *lcpp) && lcp->lcd_state == DATA_TRANSFER && (lcp->lcd_flags & X25_DG_CIRCUIT) && (lcp->lcd_dg_timer && --lcp->lcd_dg_timer == 0)) { (*lcp->lcd_upper)(NULL, lcp); } splx(s); } /* * This routine gets called when validating additions of new routes * or deletions of old ones. */ void x25_rtrequest(cmd, rt, info) int cmd; register struct rtentry *rt; struct rt_addrinfo *info; { register struct llinfo_x25 *lx = (struct llinfo_x25 *) rt->rt_llinfo; register struct pklcd *lcp; /* * would put this pk_init, except routing table doesn't exist yet. */ if (x25_dgram_sockmask == 0) { x25_dgram_sockmask = SA(rn_addmask((caddr_t) & x25_dgmask, 0, 4)->rn_key); } if (rt->rt_flags & RTF_GATEWAY) { if (rt->rt_llinfo) RTFREE((struct rtentry *) rt->rt_llinfo); rt->rt_llinfo = (cmd == RTM_ADD) ? (caddr_t) rtalloc1(rt->rt_gateway, 1) : 0; return; } if ((rt->rt_flags & RTF_HOST) == 0) return; if (cmd == RTM_DELETE) { while (rt->rt_llinfo) x25_lxfree((struct llinfo_x25 *) rt->rt_llinfo); x25_rtinvert(RTM_DELETE, rt->rt_gateway, rt); return; } if (lx == 0 && (lx = x25_lxalloc(rt)) == 0) return; if ((lcp = lx->lx_lcd) && lcp->lcd_state != READY) { /* * This can only happen on a RTM_CHANGE operation * though cmd will be RTM_ADD. */ if (lcp->lcd_ceaddr && Bcmp(rt->rt_gateway, lcp->lcd_ceaddr, lcp->lcd_ceaddr->x25_len) != 0) { x25_rtinvert(RTM_DELETE, (struct sockaddr *) lcp->lcd_ceaddr, rt); lcp->lcd_upper = 0; pk_disconnect(lcp); } lcp = 0; } x25_rtinvert(RTM_ADD, rt->rt_gateway, rt); } int x25_dont_rtinvert = 0; void x25_rtinvert(cmd, sa, rt) int cmd; register struct sockaddr *sa; register struct rtentry *rt; { struct rtentry *rt2 = 0; /* * rt_gateway contains PID indicating which proto * family on the other end, so will be different * from general host route via X.25. */ if (rt->rt_ifp->if_type == IFT_X25DDN || x25_dont_rtinvert) return; if (sa->sa_family != AF_CCITT) return; if (cmd != RTM_DELETE) { rtrequest(RTM_ADD, sa, rt_key(rt), x25_dgram_sockmask, RTF_PROTO2, &rt2); if (rt2) { rt2->rt_llinfo = (caddr_t) rt; rt->rt_refcnt++; } return; } rt2 = rt; if ((rt = rtalloc1(sa, 0)) == 0 || (rt->rt_flags & RTF_PROTO2) == 0 || rt->rt_llinfo != (caddr_t) rt2) { printf("x25_rtchange: inverse route screwup\n"); return; } else rt2->rt_refcnt--; rtrequest(RTM_DELETE, sa, rt_key(rt2), x25_dgram_sockmask, 0, (struct rtentry **) 0); } static struct sockaddr_x25 blank_x25 = {sizeof blank_x25, AF_CCITT}; /* * IP to X25 address routine copyright ACC, used by permission. */ union imp_addr { struct in_addr ip; struct imp { u_char s_net; u_char s_host; u_char s_lh; u_char s_impno; } imp; }; /* * The following is totally bogus and here only to preserve * the IP to X.25 translation. */ void x25_ddnip_to_ccitt(src, rt) struct sockaddr *src; register struct rtentry *rt; { register struct sockaddr_x25 *dst = (struct sockaddr_x25 *) rt->rt_gateway; union imp_addr imp_addr; int imp_no, imp_port, temp; char *x25addr = dst->x25_addr; imp_addr.ip = ((struct sockaddr_in *) src)->sin_addr; *dst = blank_x25; if ((imp_addr.imp.s_net & 0x80) == 0x00) { /* class A */ imp_no = imp_addr.imp.s_impno; imp_port = imp_addr.imp.s_host; } else if ((imp_addr.imp.s_net & 0xc0) == 0x80) { /* class B */ imp_no = imp_addr.imp.s_impno; imp_port = imp_addr.imp.s_lh; } else { /* class C */ imp_no = imp_addr.imp.s_impno / 32; imp_port = imp_addr.imp.s_impno % 32; } x25addr[0] = 12; /* length */ /* DNIC is cleared by struct copy above */ if (imp_port < 64) { /* Physical: 0000 0 IIIHH00 [SS] *//* s_impno * -> III, s_host -> HH */ x25addr[5] = 0; /* set flag bit */ x25addr[6] = imp_no / 100; x25addr[7] = (imp_no % 100) / 10; x25addr[8] = imp_no % 10; x25addr[9] = imp_port / 10; x25addr[10] = imp_port % 10; } else { /* Logical: 0000 1 RRRRR00 [SS] *//* s * _host * 256 + s_impno -> RRRRR */ temp = (imp_port << 8) + imp_no; x25addr[5] = 1; x25addr[6] = temp / 10000; x25addr[7] = (temp % 10000) / 1000; x25addr[8] = (temp % 1000) / 100; x25addr[9] = (temp % 100) / 10; x25addr[10] = temp % 10; } } /* * This routine is a sketch and is not to be believed!!!!! * * This is a utility routine to be called by x25 devices when a * call request is honored with the intent of starting datagram forwarding. */ void x25_dg_rtinit(dst, ia, af) struct sockaddr_x25 *dst; register struct x25_ifaddr *ia; int af; { struct sockaddr *sa = 0; struct rtentry *rt; struct in_addr my_addr; static struct sockaddr_in sin = {sizeof(sin), AF_INET}; if (ia->ia_ifp->if_type == IFT_X25DDN && af == AF_INET) { /* * Inverse X25 to IP mapping copyright and courtesy ACC. */ int imp_no, imp_port, temp; union imp_addr imp_addr; { /* * First determine our IP addr for network */ register struct in_ifaddr *ina; for (ina = in_ifaddr.tqh_first; ina != 0; ina = ina->ia_list.tqe_next) if (ina->ia_ifp == ia->ia_ifp) { my_addr = ina->ia_addr.sin_addr; break; } } { register char *x25addr = dst->x25_addr; switch (x25addr[5] & 0x0f) { case 0:/* Physical: 0000 0 IIIHH00 [SS] */ imp_no = ((int) (x25addr[6] & 0x0f) * 100) + ((int) (x25addr[7] & 0x0f) * 10) + ((int) (x25addr[8] & 0x0f)); imp_port = ((int) (x25addr[9] & 0x0f) * 10) + ((int) (x25addr[10] & 0x0f)); break; case 1:/* Logical: 0000 1 RRRRR00 [SS] */ temp = ((int) (x25addr[6] & 0x0f) * 10000) + ((int) (x25addr[7] & 0x0f) * 1000) + ((int) (x25addr[8] & 0x0f) * 100) + ((int) (x25addr[9] & 0x0f) * 10) + ((int) (x25addr[10] & 0x0f)); imp_port = temp >> 8; imp_no = temp & 0xff; break; default: return; } imp_addr.ip = my_addr; if ((imp_addr.imp.s_net & 0x80) == 0x00) { /* class A */ imp_addr.imp.s_host = imp_port; imp_addr.imp.s_impno = imp_no; imp_addr.imp.s_lh = 0; } else if ((imp_addr.imp.s_net & 0xc0) == 0x80) { /* class B */ imp_addr.imp.s_lh = imp_port; imp_addr.imp.s_impno = imp_no; } else { /* class C */ imp_addr.imp.s_impno = (imp_no << 5) + imp_port; } } sin.sin_addr = imp_addr.ip; sa = (struct sockaddr *) & sin; } else { /* * This uses the X25 routing table to do inverse * lookup of x25 address to sockaddr. */ if ((rt = rtalloc1(SA(dst), 0)) != NULL) { sa = rt->rt_gateway; rt->rt_refcnt--; } } /* * Call to rtalloc1 will create rtentry for reverse path to callee by * virtue of cloning magic and will allocate space for local control * block. */ if (sa && (rt = rtalloc1(sa, 1))) rt->rt_refcnt--; } int x25_startproto = 1; void pk_init() { /* * warning, sizeof (struct sockaddr_x25) > 32, * but contains no data of interest beyond 32 */ if (x25_startproto) { pk_protolisten(0xcc, 1, x25_dgram_incoming); pk_protolisten(0x81, 1, x25_dgram_incoming); } } struct x25_dgproto { u_char spi; u_char spilen; int (*f) __P((struct mbuf *, void *)); } x25_dgprototab[] = { #if defined(ISO) && defined(TPCONS) { 0x0, 0, tp_incoming }, #endif { 0xcc, 1, x25_dgram_incoming }, { 0xcd, 1, x25_dgram_incoming }, { 0x81, 1, x25_dgram_incoming }, }; int pk_user_protolisten(info) register u_char *info; { register struct x25_dgproto *dp = x25_dgprototab + ((sizeof x25_dgprototab) / (sizeof *dp)); register struct pklcd *lcp; while (dp > x25_dgprototab) if ((--dp)->spi == info[0]) goto gotspi; return ESRCH; gotspi:if (info[1]) return pk_protolisten(dp->spi, dp->spilen, dp->f); for (lcp = pk_listenhead; lcp; lcp = lcp->lcd_listen) if (lcp->lcd_laddr.x25_udlen == dp->spilen && Bcmp(&dp->spi, lcp->lcd_laddr.x25_udata, dp->spilen) == 0) { pk_disconnect(lcp); return 0; } return ESRCH; } /* * This routine transfers an X.25 circuit to or from a routing entry. * If the supplied circuit is * in DATA_TRANSFER state, it is added to the * routing entry. If freshly allocated, it glues back the vc from * the rtentry to the socket. */ int pk_rtattach(so, m0) register struct socket *so; struct mbuf *m0; { register struct pklcd *lcp = (struct pklcd *) so->so_pcb; register struct mbuf *m = m0; struct sockaddr *dst = mtod(m, struct sockaddr *); register struct rtentry *rt = rtalloc1(dst, 0); register struct llinfo_x25 *lx; caddr_t cp; #define ROUNDUP(a) \ ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) #define transfer_sockbuf(s, f, l) \ while ((m = (s)->sb_mb) != NULL) \ {(s)->sb_mb = m->m_act; m->m_act = 0; sbfree((s), m); f;} if (rt) rt->rt_refcnt--; cp = (dst->sa_len < m->m_len) ? ROUNDUP(dst->sa_len) + (caddr_t) dst : 0; while (rt && ((cp == 0 && rt_mask(rt) != 0) || (cp != 0 && (rt_mask(rt) == 0 || Bcmp(cp, rt_mask(rt), rt_mask(rt)->sa_len)) != 0))) rt = (struct rtentry *) rt->rt_nodes->rn_dupedkey; if (rt == 0 || (rt->rt_flags & RTF_GATEWAY) || (lx = (struct llinfo_x25 *) rt->rt_llinfo) == 0) return ESRCH; if (lcp == 0) return ENOTCONN; switch (lcp->lcd_state) { default: return ENOTCONN; case READY: /* Detach VC from rtentry */ if (lx->lx_lcd == 0) return ENOTCONN; lcp->lcd_so = 0; pk_close(lcp); lcp = lx->lx_lcd; if (lx->lx_list.le_next->lx_rt == rt) x25_lxfree(lx); lcp->lcd_so = so; lcp->lcd_upper = 0; lcp->lcd_upnext = 0; transfer_sockbuf(&lcp->lcd_sb, sbappendrecord(&so->so_snd, m), &so->so_snd); soisconnected(so); return 0; case DATA_TRANSFER: /* Add VC to rtentry */ lcp->lcd_so = 0; lcp->lcd_sb = so->so_snd; /* structure copy */ bzero((caddr_t) & so->so_snd, sizeof(so->so_snd)); /* XXXXXX */ so->so_pcb = 0; x25_rtattach(lcp, rt); transfer_sockbuf(&so->so_rcv, x25_ifinput(m, lcp), lcp); soisdisconnected(so); } return 0; } int x25_rtattach(lcp0, rt) register struct pklcd *lcp0; struct rtentry *rt; { register struct llinfo_x25 *lx = (struct llinfo_x25 *) rt->rt_llinfo; register struct pklcd *lcp; register struct mbuf *m; if ((lcp = lx->lx_lcd) != NULL) { /* adding an additional VC */ if (lcp->lcd_state == READY) { transfer_sockbuf(&lcp->lcd_sb, pk_output(lcp0), lcp0); lcp->lcd_upper = 0; pk_close(lcp); } else { lx = x25_lxalloc(rt); if (lx == 0) return ENOBUFS; } } lx->lx_lcd = lcp = lcp0; lcp->lcd_upper = x25_ifinput; lcp->lcd_upnext = (caddr_t) lx; return 0; }