/* * demand.c - Support routines for demand-dialling. * * Copyright (c) 1996-2002 Paul Mackerras. 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. The name(s) of the authors of this software must not be used to * endorse or promote products derived from this software without * prior written permission. * * 3. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by Paul Mackerras * ". * * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #define RCSID "$Id: demand.c,v 1.19 2004/11/04 10:02:26 paulus Exp $" #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef PPP_FILTER #include #endif #include "pppd.h" #include "fsm.h" #include "ipcp.h" #include "lcp.h" static const char rcsid[] = RCSID; char *frame; int framelen; int framemax; int escape_flag; int flush_flag; int fcs; struct packet { int length; struct packet *next; unsigned char data[1]; }; struct packet *pend_q; struct packet *pend_qtail; static int active_packet __P((unsigned char *, int)); /* * demand_conf - configure the interface for doing dial-on-demand. */ void demand_conf() { int i; struct protent *protp; /* framemax = lcp_allowoptions[0].mru; if (framemax < PPP_MRU) */ framemax = PPP_MRU; framemax += PPP_HDRLEN + PPP_FCSLEN; frame = malloc(framemax); if (frame == NULL) novm("demand frame"); framelen = 0; pend_q = NULL; escape_flag = 0; flush_flag = 0; fcs = PPP_INITFCS; netif_set_mtu(0, MIN(lcp_allowoptions[0].mru, PPP_MRU)); if (ppp_send_config(0, PPP_MRU, (u_int32_t) 0, 0, 0) < 0 || ppp_recv_config(0, PPP_MRU, (u_int32_t) 0, 0, 0) < 0) fatal("Couldn't set up demand-dialled PPP interface: %m"); #ifdef PPP_FILTER set_filters(&pass_filter, &active_filter); #endif /* * Call the demand_conf procedure for each protocol that's got one. */ for (i = 0; (protp = protocols[i]) != NULL; ++i) if (protp->enabled_flag && protp->demand_conf != NULL) if (!((*protp->demand_conf)(0))) die(1); } /* * demand_block - set each network protocol to block further packets. */ void demand_block() { int i; struct protent *protp; for (i = 0; (protp = protocols[i]) != NULL; ++i) if (protp->enabled_flag && protp->demand_conf != NULL) sifnpmode(0, protp->protocol & ~0x8000, NPMODE_QUEUE); get_loop_output(); } /* * demand_discard - set each network protocol to discard packets * with an error. */ void demand_discard() { struct packet *pkt, *nextpkt; int i; struct protent *protp; for (i = 0; (protp = protocols[i]) != NULL; ++i) if (protp->enabled_flag && protp->demand_conf != NULL) sifnpmode(0, protp->protocol & ~0x8000, NPMODE_ERROR); get_loop_output(); /* discard all saved packets */ for (pkt = pend_q; pkt != NULL; pkt = nextpkt) { nextpkt = pkt->next; free(pkt); } pend_q = NULL; framelen = 0; flush_flag = 0; escape_flag = 0; fcs = PPP_INITFCS; } /* * demand_unblock - set each enabled network protocol to pass packets. */ void demand_unblock() { int i; struct protent *protp; for (i = 0; (protp = protocols[i]) != NULL; ++i) if (protp->enabled_flag && protp->demand_conf != NULL) sifnpmode(0, protp->protocol & ~0x8000, NPMODE_PASS); } /* * FCS lookup table as calculated by genfcstab. */ static u_short fcstab[256] = { 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 }; /* * loop_chars - process characters received from the loopback. * Calls loop_frame when a complete frame has been accumulated. * Return value is 1 if we need to bring up the link, 0 otherwise. */ int loop_chars(p, n) unsigned char *p; int n; { int c, rv; rv = 0; for (; n > 0; --n) { c = *p++; if (c == PPP_FLAG) { if (!escape_flag && !flush_flag && framelen > 2 && fcs == PPP_GOODFCS) { framelen -= 2; if (loop_frame((unsigned char *)frame, framelen)) rv = 1; } framelen = 0; flush_flag = 0; escape_flag = 0; fcs = PPP_INITFCS; continue; } if (flush_flag) continue; if (escape_flag) { c ^= PPP_TRANS; escape_flag = 0; } else if (c == PPP_ESCAPE) { escape_flag = 1; continue; } if (framelen >= framemax) { flush_flag = 1; continue; } frame[framelen++] = c; fcs = PPP_FCS(fcs, c); } return rv; } /* * loop_frame - given a frame obtained from the loopback, * decide whether to bring up the link or not, and, if we want * to transmit this frame later, put it on the pending queue. * Return value is 1 if we need to bring up the link, 0 otherwise. * We assume that the kernel driver has already applied the * pass_filter, so we won't get packets it rejected. * We apply the active_filter to see if we want this packet to * bring up the link. */ int loop_frame(frame, len) unsigned char *frame; int len; { struct packet *pkt; /* dbglog("from loop: %P", frame, len); */ if (len < PPP_HDRLEN) return 0; if ((PPP_PROTOCOL(frame) & 0x8000) != 0) return 0; /* shouldn't get any of these anyway */ if (!active_packet(frame, len)) return 0; pkt = (struct packet *) malloc(sizeof(struct packet) + len); if (pkt != NULL) { pkt->length = len; pkt->next = NULL; memcpy(pkt->data, frame, len); if (pend_q == NULL) pend_q = pkt; else pend_qtail->next = pkt; pend_qtail = pkt; } return 1; } /* * demand_rexmit - Resend all those frames which we got via the * loopback, now that the real serial link is up. */ void demand_rexmit(proto) int proto; { struct packet *pkt, *prev, *nextpkt; prev = NULL; pkt = pend_q; pend_q = NULL; for (; pkt != NULL; pkt = nextpkt) { nextpkt = pkt->next; if (PPP_PROTOCOL(pkt->data) == proto) { output(0, pkt->data, pkt->length); free(pkt); } else { if (prev == NULL) pend_q = pkt; else prev->next = pkt; prev = pkt; } } pend_qtail = prev; if (prev != NULL) prev->next = NULL; } /* * Scan a packet to decide whether it is an "active" packet, * that is, whether it is worth bringing up the link for. */ static int active_packet(p, len) unsigned char *p; int len; { int proto, i; struct protent *protp; if (len < PPP_HDRLEN) return 0; proto = PPP_PROTOCOL(p); #ifdef PPP_FILTER if (pass_filter.bf_len != 0 && bpf_filter(pass_filter.bf_insns, p, len, len) == 0) return 0; if (active_filter.bf_len != 0 && bpf_filter(active_filter.bf_insns, p, len, len) == 0) return 0; #endif for (i = 0; (protp = protocols[i]) != NULL; ++i) { if (protp->protocol < 0xC000 && (protp->protocol & ~0x8000) == proto) { if (!protp->enabled_flag) return 0; if (protp->active_pkt == NULL) return 1; return (*protp->active_pkt)(p, len); } } return 0; /* not a supported protocol !!?? */ }