+/*
+ * Copyright (C) Dirk Husemann, Computer Science Department IV,
+ * University of Erlangen-Nuremberg, Germany, 1990, 1991, 1992
+ * Copyright (c) 1992 Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Dirk Husemann and the Computer Science Department (IV) of
+ * the University of Erlangen-Nuremberg, Germany.
+ *
+ * %sccs.include.redist.c%
+ *
+ * @(#)llc_input.c 7.1 (Berkeley) %G%
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/mbuf.h>
+#include <sys/domain.h>
+#include <sys/socket.h>
+#include <sys/protosw.h>
+#include <sys/errno.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/if_llc.h>
+#include <net/route.h>
+
+#include <netccitt/dll.h>
+#include <netccitt/llc_var.h>
+
+/*
+ * This module implements LLC as specified by ISO 8802-2.
+ */
+
+
+/*
+ * llcintr() handles all LLC frames (except ISO CLNS ones for the time being)
+ * and tries to pass them on to the appropriate network layer entity.
+ */
+void
+llcintr()
+{
+ register struct mbuf *m;
+ register int i;
+ register int frame_kind;
+ register u_char cmdrsp;
+ struct llc_linkcb *linkp;
+ struct rtentry *sirt;
+ struct npaidbentry *sapinfo;
+ struct sdl_hdr *sdlhdr;
+ struct llc *frame;
+ char *c;
+ long expected_len;
+
+ struct ifnet *ifp;
+ struct rtentry *llrt;
+ struct rtentry *nlrt;
+
+ struct mbuf *m_adj();
+
+ for (;;) {
+ i = splimp();
+ IF_DEQUEUE(&llcintrq, m);
+ splx(i);
+ if (m == 0)
+ break;
+#ifdef DIAGNOSTIC
+ if ((m->m_flags & M_PKTHDR) == 0)
+ panic("llcintr no HDR");
+#endif
+ /*
+ * Get ifp this packet was received on
+ */
+ ifp = m->m_pkthdr.rcvif;
+
+ sdlhdr = mtod(m, struct sdl_hdr *);
+
+ /*
+ * [Copied from net/ip_input.c]
+ *
+ * Check that the amount of data in the buffers is
+ * at least as much as the LLC header tells us.
+ * Trim mbufs if longer than expected.
+ * Drop packets if shorter than we think they are.
+ *
+ * Layout of mbuf chain at this point:
+ *
+ * +-------------------------------+----+ -\
+ * | sockaddr_dl src - sdlhdr_src | 20 | \
+ * +-------------------------------+----+ |
+ * | sockaddr_dl dst - sdlhdr_dst | 20 | > sizeof(struct sdl_hdr) == 44
+ * +-------------------------------+----+ |
+ * | LLC frame len - sdlhdr_len | 04 | /
+ * +-------------------------------+----+ -/
+ * /
+ * | m_next
+ * \
+ * +----------------------------+----+ -\
+ * | llc DSAP | 01 | \
+ * +----------------------------+----+ |
+ * | llc SSAP | 01 | |
+ * +----------------------------+----+ > sdlhdr_len
+ * | llc control | 01 | |
+ * +----------------------------+----+ |
+ * | ... | | /
+ * -/
+ *
+ * Thus the we expect to have exactly
+ * (sdlhdr->sdlhdr_len+sizeof(struct sdl_hdr)) in the mbuf chain
+ */
+ expected_len = sdlhdr->sdlhdr_len + sizeof(struct sdl_hdr);
+
+ if (m->m_pkthdr.len < expected_len) {
+ m_freem(m);
+ continue;
+ }
+ if (m->m_pkthdr.len > expected_len) {
+ if (m->m_len == m->m_pkthdr.len) {
+ m->m_len = expected_len;
+ m->m_pkthdr.len = expected_len;
+ } else
+ m_adj(m, expected_len - m->m_pkthdr.len);
+ }
+
+ /*
+ * Get llc header
+ */
+ if (m->m_len > sizeof(struct sdl_hdr))
+ frame = mtod((struct mbuf *)((struct sdl_hdr*)(m+1)),
+ struct llc *);
+ else frame = mtod(m->m_next, struct llc *);
+ if (frame == (struct llc *) NULL)
+ panic("llcintr no llc header");
+
+ /*
+ * Now check for bogus I/S frame, i.e. those with a control
+ * field telling us they're an I/S frame yet their length
+ * is less than the established I/S frame length (DSAP + SSAP +
+ * control + N(R)&P/F = 4) --- we drop those suckers
+ */
+ if (((frame->llc_control & 0x03) != 0x03)
+ && ((expected_len - sizeof(struct sdl_hdr)) < LLC_ISFRAMELEN)) {
+ m_freem(m);
+ printf("llc: hurz error\n");
+ continue;
+ }
+
+ /*
+ * Get link control block for the addressed link connection.
+ * If there is none we take care of it later on.
+ */
+ cmdrsp = (frame->llc_ssap & 0x01);
+ frame->llc_ssap &= ~0x01;
+ if (llrt = rtalloc1(&sdlhdr->sdlhdr_src, 0))
+ llrt->rt_refcnt--;
+#ifdef notyet
+ else llrt = npaidb_enter(&sdlhdr->sdlhdr_src, 0, 0, 0);
+#endif /* notyet */
+ else {
+ /*
+ * We cannot do anything currently here as we
+ * don't `know' this link --- drop it
+ */
+ m_freem(m);
+ continue;
+ }
+ linkp = ((struct npaidbentry *)(llrt->rt_llinfo))->np_link;
+ nlrt = ((struct npaidbentry *)(llrt->rt_llinfo))->np_rt;
+
+ /*
+ * If the link is not existing right now, we can try and look up
+ * the SAP info block.
+ */
+ if ((linkp == 0) && frame->llc_ssap)
+ sapinfo = llc_getsapinfo(frame->llc_dsap, ifp);
+
+ /*
+ * Handle XID and TEST frames
+ * XID: if DLSAP == 0, return type-of-services
+ * window-0
+ * DLSAP-0
+ * format-identifier-?
+ * if DLSAP != 0, locate sapcb and return
+ * type-of-services
+ * SAP-window
+ * format-identifier-?
+ * TEST: swap (snpah_dst, snpah_src) and return frame
+ *
+ * Also toggle the CMD/RESP bit
+ *
+ * Is this behaviour correct? Check ISO 8802-2 (90)!
+ */
+ frame_kind = llc_decode(frame, (struct llc_linkcb *)0);
+ switch(frame_kind) {
+ case LLCFT_XID:
+ if (linkp || sapinfo) {
+ if (linkp)
+ frame->llc_window = linkp->llcl_window;
+ else frame->llc_window = sapinfo->si_window;
+ frame->llc_fid = 9; /* XXX */
+ frame->llc_class = sapinfo->si_class;
+ frame->llc_ssap = frame->llc_dsap;
+ } else {
+ frame->llc_window = 0;
+ frame->llc_fid = 9;
+ frame->llc_class = 1;
+ frame->llc_dsap = frame->llc_ssap = 0;
+ }
+
+ /* fall thru to */
+ case LLCFT_TEST:
+ sdl_swapaddr(&(mtod(m, struct sdl_hdr *)->sdlhdr_dst),
+ &(mtod(m, struct sdl_hdr *)->sdlhdr_src));
+
+ /* Now set the CMD/RESP bit */
+ frame->llc_ssap |= (cmdrsp == 0x0 ? 0x1 : 0x0);
+
+ /* Ship it out again */
+ (*ifp->if_output)(ifp, m,
+ (struct sockaddr *) &(mtod(m, struct sdl_hdr *)->sdlhdr_dst),
+ (struct rtentry *) 0);
+ continue;
+ }
+
+ /*
+ * Create link control block in case it is not existing
+ */
+ if (linkp == 0 && sapinfo) {
+ if ((linkp = llc_newlink(&sdlhdr->sdlhdr_src, ifp, nlrt,
+ (nlrt == 0) ? 0 : nlrt->rt_llinfo,
+ llrt)) == 0) {
+ printf("llcintr: couldn't create new link\n");
+ m_freem(m);
+ continue;
+ }
+ ((struct npaidbentry *)llrt->rt_llinfo)->np_link = linkp;
+ } else if (linkp == 0) {
+ /* The link is not known to us, drop the frame and continue */
+ m_freem(m);
+ continue;
+ }
+
+ /*
+ * Drop SNPA header and get rid of empty mbuf at the
+ * front of the mbuf chain (I don't like 'em)
+ */
+ m_adj(m, sizeof(struct sdl_hdr));
+ /*
+ * LLC_UFRAMELEN is sufficient, m_pullup() will pull up
+ * the min(m->m_len, maxprotohdr_len [=40]) thus doing
+ * the trick ...
+ */
+ if ((m = m_pullup(m, LLC_UFRAMELEN)))
+ /*
+ * Pass it on thru the elements of procedure
+ */
+ llc_input(linkp, m, cmdrsp);
+ }
+ return;
+}
+
+/*
+ * llc_input() --- We deal with the various incoming frames here.
+ * Basically we (indirectly) call the appropriate
+ * state handler function that's pointed to by
+ * llcl_statehandler.
+ *
+ * The statehandler returns an action code ---
+ * further actions like
+ * o notify network layer
+ * o block further sending
+ * o deblock link
+ * o ...
+ * are then enacted accordingly.
+ */
+llc_input(struct llc_linkcb *linkp, struct mbuf *m, u_char cmdrsp)
+{
+ int frame_kind;
+ int pollfinal;
+ int action = 0;
+ struct llc *frame;
+ struct ifnet *ifp = linkp->llcl_if;
+
+ if ((frame = mtod(m, struct llc *)) == (struct llc *) 0) {
+ m_freem(m);
+ return 0;
+ }
+ pollfinal = ((frame->llc_control & 0x03) == 0x03) ?
+ LLCGBITS(frame->llc_control, u_pf) :
+ LLCGBITS(frame->llc_control_ext, s_pf);
+
+ /*
+ * first decode the frame
+ */
+ frame_kind = llc_decode(frame, linkp);
+
+ switch (action = llc_statehandler(linkp, frame, frame_kind, cmdrsp,
+ pollfinal)) {
+ case LLC_DATA_INDICATION:
+ m_adj(m, LLC_ISFRAMELEN);
+ if (m = m_pullup(m, NLHDRSIZEGUESS)) {
+ m->m_pkthdr.rcvif = (struct ifnet *)linkp->llcl_nlnext;
+ (*linkp->llcl_sapinfo->si_input)(m);
+ }
+ break;
+ }
+
+ /* release mbuf if not an info frame */
+ if (action != LLC_DATA_INDICATION && m)
+ m_freem(m);
+
+ /* try to get frames out ... */
+ llc_start(linkp);
+
+ return 0;
+}
+
+/*
+ * This routine is called by configuration setup. It sets up a station control
+ * block and notifies all registered upper level protocols.
+ */
+caddr_t
+llc_ctlinput(int prc, struct sockaddr *addr, caddr_t info)
+{
+ struct ifnet *ifp;
+ struct ifaddr *ifa;
+ struct dll_ctlinfo *ctlinfo = (struct dll_ctlinfo *)info;
+ u_char sap;
+ struct dllconfig *config;
+ caddr_t pcb;
+ struct rtentry *nlrt;
+ struct rtentry *llrt;
+ struct llc_linkcb *linkp;
+ register int i;
+
+ /* info must point to something valid at all times */
+ if (info == 0)
+ return 0;
+
+ if (prc == PRC_IFUP || prc == PRC_IFDOWN) {
+ /* we use either this set ... */
+ ifa = ifa_ifwithaddr(addr);
+ ifp = ifa ? ifa->ifa_ifp : 0;
+ if (ifp == 0)
+ return 0;
+
+ sap = ctlinfo->dlcti_lsap;
+ config = ctlinfo->dlcti_cfg;
+ pcb = (caddr_t) 0;
+ nlrt = (struct rtentry *) 0;
+ } else {
+ /* or this one */
+ sap = 0;
+ config = (struct dllconfig *) 0;
+ pcb = ctlinfo->dlcti_pcb;
+ nlrt = ctlinfo->dlcti_rt;
+
+ if ((llrt = rtalloc1(nlrt->rt_gateway, 0)))
+ llrt->rt_refcnt--;
+ else return 0;
+
+ linkp = ((struct npaidbentry *)llrt->rt_llinfo)->np_link;
+ }
+
+ switch (prc) {
+ case PRC_IFUP:
+ (void) llc_setsapinfo(ifp, addr->sa_family, sap, config);
+ return 0;
+
+ case PRC_IFDOWN: {
+ register struct llc_linkcb *linkp;
+ register struct llc_linkcb *nlinkp;
+ register int i;
+
+ /*
+ * All links are accessible over the doubly linked list llccb_q
+ */
+ if (!LQEMPTY) {
+ /*
+ * A for-loop is not that great an idea as the linkp
+ * will get deleted by llc_timer()
+ */
+ linkp = LQFIRST;
+ while (LQVALID(linkp)) {
+ nlinkp = LQNEXT(linkp);
+ if (linkp->llcl_if = ifp) {
+ i = splimp();
+ (void)llc_statehandler(linkp, (struct llc *)0,
+ NL_DISCONNECT_REQUEST,
+ 0, 1);
+ splx(i);
+ }
+ linkp = nlinkp;
+ }
+ }
+ }
+
+ case PRC_CONNECT_REQUEST:
+ if (linkp == 0) {
+ if ((linkp = llc_newlink((struct sockaddr_dl *) nlrt->rt_gateway,
+ nlrt->rt_ifp, nlrt,
+ pcb, llrt)) == 0)
+ return (0);
+ ((struct npaidbentry *)llrt->rt_llinfo)->np_link = linkp;
+ i = splimp();
+ (void)llc_statehandler(linkp, (struct llc *) 0,
+ NL_CONNECT_REQUEST, 0, 1);
+ splx(i);
+ }
+ return ((caddr_t)linkp);
+
+ case PRC_DISCONNECT_REQUEST:
+ if (linkp == 0)
+ panic("no link control block!");
+
+ i = splimp();
+ (void)llc_statehandler(linkp, (struct llc *) 0,
+ NL_DISCONNECT_REQUEST, 0, 1);
+ splx(i);
+
+ /*
+ * The actual removal of the link control block is done by the
+ * cleaning neutrum (i.e. llc_timer()).
+ */
+ break;
+
+ case PRC_RESET_REQUEST:
+ if (linkp == 0)
+ panic("no link control block!");
+
+ i = splimp();
+ (void)llc_statehandler(linkp, (struct llc *) 0,
+ NL_RESET_REQUEST, 0, 1);
+ splx(i);
+
+ break;
+
+ }
+
+ return 0;
+}
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