+/* pppol2tp.c - pppd plugin to implement PPPoL2TP protocol
+ * for Linux using kernel pppol2tp support.
+ *
+ * Requires kernel pppol2tp driver which is integrated into the kernel
+ * from 2.6.23 onwards. For earlier kernels, a version can be obtained
+ * from the OpenL2TP project at
+ * http://www.sourceforge.net/projects/openl2tp/
+ *
+ * Original by Martijn van Oosterhout <kleptog@svana.org>
+ * Modified by jchapman@katalix.com
+ *
+ * Heavily based upon pppoatm.c: original notice follows
+ *
+ * Copyright 2000 Mitchell Blank Jr.
+ * Based in part on work from Jens Axboe and Paul Mackerras.
+ * Updated to ppp-2.4.1 by Bernhard Kaindl
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "pppd.h"
+#include "pathnames.h"
+#include "fsm.h"
+#include "lcp.h"
+#include "ccp.h"
+#include "ipcp.h"
+#include <sys/stat.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <linux/version.h>
+#include <linux/sockios.h>
+#ifndef aligned_u64
+/* should be defined in sys/types.h */
+#define aligned_u64 unsigned long long __attribute__((aligned(8)))
+#endif
+#include <linux/types.h>
+#include <linux/if_ether.h>
+#include <linux/ppp_defs.h>
+#include <linux/if_ppp.h>
+#include <linux/if_pppox.h>
+#include <linux/if_pppol2tp.h>
+
+/* should be added to system's socket.h... */
+#ifndef SOL_PPPOL2TP
+#define SOL_PPPOL2TP 273
+#endif
+
+const char pppd_version[] = VERSION;
+
+static int setdevname_pppol2tp(char **argv);
+
+static int pppol2tp_fd = -1;
+static char *pppol2tp_fd_str;
+static bool pppol2tp_lns_mode = 0;
+static bool pppol2tp_recv_seq = 0;
+static bool pppol2tp_send_seq = 0;
+static int pppol2tp_debug_mask = 0;
+static int pppol2tp_reorder_timeout = 0;
+static char pppol2tp_ifname[32] = { 0, };
+int pppol2tp_tunnel_id = 0;
+int pppol2tp_session_id = 0;
+
+static int device_got_set = 0;
+struct channel pppol2tp_channel;
+
+static void (*old_snoop_recv_hook)(unsigned char *p, int len) = NULL;
+static void (*old_snoop_send_hook)(unsigned char *p, int len) = NULL;
+static void (*old_ip_up_hook)(void) = NULL;
+static void (*old_ip_down_hook)(void) = NULL;
+
+/* Hook provided to allow other plugins to handle ACCM changes */
+void (*pppol2tp_send_accm_hook)(int tunnel_id, int session_id,
+ uint32_t send_accm, uint32_t recv_accm) = NULL;
+
+/* Hook provided to allow other plugins to handle IP up/down */
+void (*pppol2tp_ip_updown_hook)(int tunnel_id, int session_id, int up) = NULL;
+
+static option_t pppol2tp_options[] = {
+ { "pppol2tp", o_special, &setdevname_pppol2tp,
+ "FD for PPPoL2TP socket", OPT_DEVNAM | OPT_A2STRVAL,
+ &pppol2tp_fd_str },
+ { "pppol2tp_lns_mode", o_bool, &pppol2tp_lns_mode,
+ "PPPoL2TP LNS behavior. Default off.",
+ OPT_PRIO | OPRIO_CFGFILE },
+ { "pppol2tp_send_seq", o_bool, &pppol2tp_send_seq,
+ "PPPoL2TP enable sequence numbers in transmitted data packets. "
+ "Default off.",
+ OPT_PRIO | OPRIO_CFGFILE },
+ { "pppol2tp_recv_seq", o_bool, &pppol2tp_recv_seq,
+ "PPPoL2TP enforce sequence numbers in received data packets. "
+ "Default off.",
+ OPT_PRIO | OPRIO_CFGFILE },
+ { "pppol2tp_reorderto", o_int, &pppol2tp_reorder_timeout,
+ "PPPoL2TP data packet reorder timeout. Default 0 (no reordering).",
+ OPT_PRIO },
+ { "pppol2tp_debug_mask", o_int, &pppol2tp_debug_mask,
+ "PPPoL2TP debug mask. Default: no debug.",
+ OPT_PRIO },
+ { "pppol2tp_ifname", o_string, &pppol2tp_ifname,
+ "Set interface name of PPP interface",
+ OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, 16 },
+ { "pppol2tp_tunnel_id", o_int, &pppol2tp_tunnel_id,
+ "PPPoL2TP tunnel_id.",
+ OPT_PRIO },
+ { "pppol2tp_session_id", o_int, &pppol2tp_session_id,
+ "PPPoL2TP session_id.",
+ OPT_PRIO },
+ { NULL }
+};
+
+static int setdevname_pppol2tp(char **argv)
+{
+ union {
+ char buffer[128];
+ struct sockaddr pppol2tp;
+ } s;
+ int len = sizeof(s);
+ char **a;
+ int tmp;
+ int tmp_len = sizeof(tmp);
+
+ if (device_got_set)
+ return 0;
+
+ if (!int_option(*argv, &pppol2tp_fd))
+ return 0;
+
+ if(getsockname(pppol2tp_fd, (struct sockaddr *)&s, &len) < 0) {
+ fatal("Given FD for PPPoL2TP socket invalid (%s)",
+ strerror(errno));
+ }
+ if(s.pppol2tp.sa_family != AF_PPPOX) {
+ fatal("Socket of not a PPPoX socket");
+ }
+
+ /* Do a test getsockopt() to ensure that the kernel has the necessary
+ * feature available.
+ */
+ if (getsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_DEBUG,
+ &tmp, &tmp_len) < 0) {
+ fatal("PPPoL2TP kernel driver not installed");
+ }
+
+ /* Setup option defaults. Compression options are disabled! */
+
+ modem = 0;
+
+ lcp_allowoptions[0].neg_accompression = 1;
+ lcp_wantoptions[0].neg_accompression = 0;
+
+ lcp_allowoptions[0].neg_pcompression = 1;
+ lcp_wantoptions[0].neg_pcompression = 0;
+
+ ccp_allowoptions[0].deflate = 0;
+ ccp_wantoptions[0].deflate = 0;
+
+ ipcp_allowoptions[0].neg_vj = 0;
+ ipcp_wantoptions[0].neg_vj = 0;
+
+ ccp_allowoptions[0].bsd_compress = 0;
+ ccp_wantoptions[0].bsd_compress = 0;
+
+ the_channel = &pppol2tp_channel;
+ device_got_set = 1;
+
+ return 1;
+}
+
+static int connect_pppol2tp(void)
+{
+ if(pppol2tp_fd == -1) {
+ fatal("No PPPoL2TP FD specified");
+ }
+
+ return pppol2tp_fd;
+}
+
+static void disconnect_pppol2tp(void)
+{
+ if (pppol2tp_fd >= 0) {
+ close(pppol2tp_fd);
+ pppol2tp_fd = -1;
+ }
+}
+
+static void send_config_pppol2tp(int mtu,
+ u_int32_t asyncmap,
+ int pcomp,
+ int accomp)
+{
+ struct ifreq ifr;
+ int on = 1;
+ int fd;
+ char reorderto[16];
+ char tid[8];
+ char sid[8];
+
+ if (pppol2tp_ifname[0]) {
+ struct ifreq ifr;
+ int fd;
+
+ fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (fd >= 0) {
+ memset (&ifr, '\0', sizeof (ifr));
+ strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+ strlcpy(ifr.ifr_newname, pppol2tp_ifname,
+ sizeof(ifr.ifr_name));
+ ioctl(fd, SIOCSIFNAME, (caddr_t) &ifr);
+ strlcpy(ifname, pppol2tp_ifname, 32);
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_CONTROL) {
+ dbglog("ppp%d: interface name %s",
+ ifunit, ifname);
+ }
+ }
+ close(fd);
+ }
+
+ if ((lcp_allowoptions[0].mru > 0) && (mtu > lcp_allowoptions[0].mru)) {
+ warn("Overriding mtu %d to %d", mtu, lcp_allowoptions[0].mru);
+ mtu = lcp_allowoptions[0].mru;
+ }
+ netif_set_mtu(ifunit, mtu);
+
+ reorderto[0] = '\0';
+ if (pppol2tp_reorder_timeout > 0)
+ sprintf(&reorderto[0], "%d ", pppol2tp_reorder_timeout);
+ tid[0] = '\0';
+ if (pppol2tp_tunnel_id > 0)
+ sprintf(&tid[0], "%hu ", pppol2tp_tunnel_id);
+ sid[0] = '\0';
+ if (pppol2tp_session_id > 0)
+ sprintf(&sid[0], "%hu ", pppol2tp_session_id);
+
+ dbglog("PPPoL2TP options: %s%s%s%s%s%s%s%s%sdebugmask %d",
+ pppol2tp_recv_seq ? "recvseq " : "",
+ pppol2tp_send_seq ? "sendseq " : "",
+ pppol2tp_lns_mode ? "lnsmode " : "",
+ pppol2tp_reorder_timeout ? "reorderto " : "", reorderto,
+ pppol2tp_tunnel_id ? "tid " : "", tid,
+ pppol2tp_session_id ? "sid " : "", sid,
+ pppol2tp_debug_mask);
+
+ if (pppol2tp_recv_seq)
+ if (setsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_RECVSEQ,
+ &on, sizeof(on)) < 0)
+ fatal("setsockopt(PPPOL2TP_RECVSEQ): %m");
+ if (pppol2tp_send_seq)
+ if (setsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_SENDSEQ,
+ &on, sizeof(on)) < 0)
+ fatal("setsockopt(PPPOL2TP_SENDSEQ): %m");
+ if (pppol2tp_lns_mode)
+ if (setsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_LNSMODE,
+ &on, sizeof(on)) < 0)
+ fatal("setsockopt(PPPOL2TP_LNSMODE): %m");
+ if (pppol2tp_reorder_timeout)
+ if (setsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_REORDERTO,
+ &pppol2tp_reorder_timeout,
+ sizeof(pppol2tp_reorder_timeout)) < 0)
+ fatal("setsockopt(PPPOL2TP_REORDERTO): %m");
+ if (pppol2tp_debug_mask)
+ if (setsockopt(pppol2tp_fd, SOL_PPPOL2TP, PPPOL2TP_SO_DEBUG,
+ &pppol2tp_debug_mask, sizeof(pppol2tp_debug_mask)) < 0)
+ fatal("setsockopt(PPPOL2TP_DEBUG): %m");
+}
+
+static void recv_config_pppol2tp(int mru,
+ u_int32_t asyncmap,
+ int pcomp,
+ int accomp)
+{
+ if ((lcp_allowoptions[0].mru > 0) && (mru > lcp_allowoptions[0].mru)) {
+ warn("Overriding mru %d to mtu value %d", mru,
+ lcp_allowoptions[0].mru);
+ mru = lcp_allowoptions[0].mru;
+ }
+ if ((ifunit >= 0) && ioctl(pppol2tp_fd, PPPIOCSMRU, (caddr_t) &mru) < 0)
+ error("Couldn't set PPP MRU: %m");
+}
+
+/*****************************************************************************
+ * Snoop LCP message exchanges to capture negotiated ACCM values.
+ * When asyncmap values have been seen from both sides, give the values to
+ * L2TP.
+ * This code is derived from Roaring Penguin L2TP.
+ *****************************************************************************/
+
+static void pppol2tp_lcp_snoop(unsigned char *buf, int len, int incoming)
+{
+ static bool got_send_accm = 0;
+ static bool got_recv_accm = 0;
+ static uint32_t recv_accm = 0xffffffff;
+ static uint32_t send_accm = 0xffffffff;
+ static bool snooping = 1;
+
+ uint16_t protocol;
+ uint16_t lcp_pkt_len;
+ int opt, opt_len;
+ int reject;
+ unsigned char const *opt_data;
+ uint32_t accm;
+
+ /* Skip HDLC header */
+ buf += 2;
+ len -= 2;
+
+ /* Unreasonably short frame?? */
+ if (len <= 0) return;
+
+ /* Get protocol */
+ if (buf[0] & 0x01) {
+ /* Compressed protcol field */
+ protocol = buf[0];
+ } else {
+ protocol = ((unsigned int) buf[0]) * 256 + buf[1];
+ }
+
+ /* If it's a network protocol, stop snooping */
+ if (protocol <= 0x3fff) {
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_DEBUG) {
+ dbglog("Turning off snooping: "
+ "Network protocol %04x found.",
+ protocol);
+ }
+ snooping = 0;
+ return;
+ }
+
+ /* If it's not LCP, do not snoop */
+ if (protocol != 0xc021) {
+ return;
+ }
+
+ /* Skip protocol; go to packet data */
+ buf += 2;
+ len -= 2;
+
+ /* Unreasonably short frame?? */
+ if (len <= 0) return;
+
+ /* Look for Configure-Ack or Configure-Reject code */
+ if (buf[0] != CONFACK && buf[0] != CONFREJ) return;
+
+ reject = (buf[0] == CONFREJ);
+
+ lcp_pkt_len = ((unsigned int) buf[2]) * 256 + buf[3];
+
+ /* Something fishy with length field? */
+ if (lcp_pkt_len > len) return;
+
+ /* Skip to options */
+ len = lcp_pkt_len - 4;
+ buf += 4;
+
+ while (len > 0) {
+ /* Pull off an option */
+ opt = buf[0];
+ opt_len = buf[1];
+ opt_data = &buf[2];
+ if (opt_len > len || opt_len < 2) break;
+ len -= opt_len;
+ buf += opt_len;
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_DEBUG) {
+ dbglog("Found option type %02x; len %d", opt, opt_len);
+ }
+
+ /* We are specifically interested in ACCM */
+ if (opt == CI_ASYNCMAP && opt_len == 0x06) {
+ if (reject) {
+ /* ACCM negotiation REJECTED; use default */
+ accm = 0xffffffff;
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_DATA) {
+ dbglog("Rejected ACCM negotiation; "
+ "defaulting (%s)",
+ incoming ? "incoming" : "outgoing");
+ }
+ recv_accm = accm;
+ send_accm = accm;
+ got_recv_accm = 1;
+ got_send_accm = 1;
+ } else {
+ memcpy(&accm, opt_data, sizeof(accm));
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_DATA) {
+ dbglog("Found ACCM of %08x (%s)", accm,
+ incoming ? "incoming" : "outgoing");
+ }
+ if (incoming) {
+ recv_accm = accm;
+ got_recv_accm = 1;
+ } else {
+ send_accm = accm;
+ got_send_accm = 1;
+ }
+ }
+
+ if (got_recv_accm && got_send_accm) {
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_CONTROL) {
+ dbglog("Telling L2TP: Send ACCM = %08x; "
+ "Receive ACCM = %08x", send_accm, recv_accm);
+ }
+ if (pppol2tp_send_accm_hook != NULL) {
+ (*pppol2tp_send_accm_hook)(pppol2tp_tunnel_id,
+ pppol2tp_session_id,
+ send_accm, recv_accm);
+ }
+ got_recv_accm = 0;
+ got_send_accm = 0;
+ }
+ }
+ }
+}
+
+static void pppol2tp_lcp_snoop_recv(unsigned char *p, int len)
+{
+ if (old_snoop_recv_hook != NULL)
+ (*old_snoop_recv_hook)(p, len);
+ pppol2tp_lcp_snoop(p, len, 1);
+}
+
+static void pppol2tp_lcp_snoop_send(unsigned char *p, int len)
+{
+ if (old_snoop_send_hook != NULL)
+ (*old_snoop_send_hook)(p, len);
+ pppol2tp_lcp_snoop(p, len, 0);
+}
+
+/*****************************************************************************
+ * Interface up/down events
+ *****************************************************************************/
+
+static void pppol2tp_ip_up_hook(void)
+{
+ if (old_ip_up_hook != NULL)
+ (*old_ip_up_hook)();
+
+ if (pppol2tp_ip_updown_hook != NULL) {
+ (*pppol2tp_ip_updown_hook)(pppol2tp_tunnel_id,
+ pppol2tp_session_id, 1);
+ }
+}
+
+static void pppol2tp_ip_down_hook(void)
+{
+ if (old_ip_down_hook != NULL)
+ (*old_ip_down_hook)();
+
+ if (pppol2tp_ip_updown_hook != NULL) {
+ (*pppol2tp_ip_updown_hook)(pppol2tp_tunnel_id,
+ pppol2tp_session_id, 0);
+ }
+}
+
+/*****************************************************************************
+ * Application init
+ *****************************************************************************/
+
+static void pppol2tp_check_options(void)
+{
+ /* Enable LCP snooping for ACCM options only for LNS */
+ if (pppol2tp_lns_mode) {
+ if ((pppol2tp_tunnel_id == 0) || (pppol2tp_session_id == 0)) {
+ fatal("tunnel_id/session_id values not specified");
+ }
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_CONTROL) {
+ dbglog("Enabling LCP snooping");
+ }
+ old_snoop_recv_hook = snoop_recv_hook;
+ old_snoop_send_hook = snoop_send_hook;
+
+ snoop_recv_hook = pppol2tp_lcp_snoop_recv;
+ snoop_send_hook = pppol2tp_lcp_snoop_send;
+ }
+
+ /* Hook up ip up/down hooks to send indicator to openl2tpd
+ * that the link is up
+ */
+ old_ip_up_hook = ip_up_hook;
+ ip_up_hook = pppol2tp_ip_up_hook;
+ old_ip_down_hook = ip_down_hook;
+ ip_down_hook = pppol2tp_ip_down_hook;
+}
+
+/* Called just before pppd exits.
+ */
+static void pppol2tp_cleanup(void)
+{
+ if (pppol2tp_debug_mask & PPPOL2TP_MSG_DEBUG) {
+ dbglog("pppol2tp: exiting.");
+ }
+ disconnect_pppol2tp();
+}
+
+void plugin_init(void)
+{
+#if defined(__linux__)
+ extern int new_style_driver; /* From sys-linux.c */
+ if (!ppp_available() && !new_style_driver)
+ fatal("Kernel doesn't support ppp_generic - "
+ "needed for PPPoL2TP");
+#else
+ fatal("No PPPoL2TP support on this OS");
+#endif
+ add_options(pppol2tp_options);
+}
+
+struct channel pppol2tp_channel = {
+ options: pppol2tp_options,
+ process_extra_options: NULL,
+ check_options: &pppol2tp_check_options,
+ connect: &connect_pppol2tp,
+ disconnect: &disconnect_pppol2tp,
+ establish_ppp: &generic_establish_ppp,
+ disestablish_ppp: &generic_disestablish_ppp,
+ send_config: &send_config_pppol2tp,
+ recv_config: &recv_config_pppol2tp,
+ close: NULL,
+ cleanup: NULL
+};
projects / ppp.git / commitdiff