2 * Copyright 2015-2016 Max Staudt
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License 2 as published
6 * by the Free Software Foundation.
16 #include <sys/types.h>
17 #include <sys/socket.h>
18 #include <linux/can.h>
19 #include <linux/can/raw.h>
21 #include <sys/ioctl.h>
27 #include "vw-nm-tools.h"
31 static int nm_is_rx_frame_valid(struct NM_Main *nm, struct can_frame *frame)
33 if (frame->can_dlc < 2) {
34 printf("Skipping short frame from CAN ID %03x\n", frame->can_id);
38 if ((frame->can_id & ~(nm->max_nodes - 1)) != nm->can_base) {
39 printf("Skipping non-NM from CAN ID %03x\n", frame->can_id);
49 static void nm_update_my_next_id(struct NM_Main *nm) {
50 unsigned id = nm->my_id;
56 if (id >= nm->max_nodes) {
60 state = nm->nodes[id].state & NM_MAIN_MASK;
62 if (state == NM_MAIN_ON || state == NM_MAIN_LOGIN) {
63 /* We skip limp home nodes */
64 nm->nodes[nm->my_id].next = id;
67 } while (id != nm->my_id);
69 if (nm->nodes[nm->my_id].next == nm->my_id) {
70 /* Uh oh, we're the only one left. */
73 nm->nodes[nm->my_id].state = NM_MAIN_LOGIN;
75 /* TODO: Timeout 140ms (RCD 310) */
81 static void nm_handle_can_frame(struct NM_Main *nm, struct can_frame *frame)
86 /* Is this a valid frame within our logical network? */
87 if (!nm_is_rx_frame_valid(nm, frame)) {
91 printf("Received NM frame from CAN ID %03x\n", frame->can_id);
94 /* Parse sender, its perceived successor, and its state */
95 sender = frame->can_id & (nm->max_nodes - 1);
96 next = frame->data[0];
97 state = frame->data[1];
99 /* TODO: Validate state, it needs to be within the enum */
101 /* Skip our own frames */
102 if (sender == nm->my_id) {
106 nm->nodes[sender].next = next;
107 nm->nodes[sender].state = state;
109 switch (state & NM_MAIN_MASK) {
111 if (next == nm->nodes[nm->my_id].next
112 && nm->nodes[nm->my_id].next != nm->my_id) {
113 /* sender doesn't know we exist */
115 nm->nodes[nm->my_id].state = NM_MAIN_LOGIN;
119 /* IMPORTANT: The caller needs to check for
120 * timeouts first, i.e. no other NM frames
121 * are received until our correcting login
124 } else if (next == nm->nodes[nm->my_id].next) {
125 /* where (nm->nodes[nm->my_id].next == nm->my_id) */
127 /* It can happen when:
128 * - our sent frames don't go anywhere
129 * - we just logged in and immediately
130 * afterwards another ECU sent a regular
134 /* Let's handle this just like a LOGIN, since
135 * we're learning about a new device.
136 * See case NM_MAIN_LOGIN below for details.
139 nm_update_my_next_id(nm);
140 nm->nodes[nm->my_id].state = NM_MAIN_ON;
141 } else if (next == nm->my_id) {
143 * Reset the timeout so anyone we missed
144 * can send its login frame to correct us.
147 nm->tv.tv_usec = NM_USECS_MY_TURN;
149 /* We just got some random ON message.
150 * Reset the timer looking out for broken
154 nm->tv.tv_usec = NM_USECS_NODE_AWOL;
158 /* Note: sender != nm->my_id */
160 nm_update_my_next_id(nm);
162 /* We're not alone anymore, so let's change state. */
163 nm->nodes[nm->my_id].state = NM_MAIN_ON;
165 /* We don't reset the timeout when somebody logs in,
166 * i.e. (next == sender).
167 * Instead, we'll simply include them in the next
170 /* Actually, when a login is done as a correction,
171 * we do reset the timeout.
173 if (next != sender) {
175 nm->tv.tv_usec = NM_USECS_NODE_AWOL;
178 case NM_MAIN_LIMPHOME:
179 nm_update_my_next_id(nm);
190 static void nm_buildframe(struct NM_Main *nm, struct can_frame *frame)
192 frame->can_id = nm->can_base + nm->my_id;
194 frame->data[0] = nm->nodes[nm->my_id].next;
195 frame->data[1] = nm->nodes[nm->my_id].state;
201 static void nm_timeout_callback(struct NM_Main *nm, struct can_frame *frame)
204 nm->tv.tv_usec = NM_USECS_NODE_AWOL;
206 nm_buildframe(nm, frame);
212 static void nm_start(struct NM_Main *nm, struct can_frame *frame)
215 nm->tv.tv_usec = 50000;
219 nm->nodes[nm->my_id].next = nm->my_id;
220 nm->nodes[nm->my_id].state = NM_MAIN_LOGIN;
222 nm_buildframe(nm, frame);
228 static int net_init(char *ifname)
232 struct sockaddr_can addr;
234 struct can_filter fi;
236 s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
242 /* Convert interface name to index */
243 memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
244 strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
245 if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
246 perror("SIOCGIFINDEX");
250 /* Open the CAN interface */
251 memset(&addr, 0, sizeof(addr));
252 addr.can_family = AF_CAN;
253 addr.can_ifindex = ifr.ifr_ifindex;
254 if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
259 recv_own_msgs = 1; /* 0 = disabled (default), 1 = enabled */
260 setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS,
261 &recv_own_msgs, sizeof(recv_own_msgs));
263 /* Handle only 32 NM IDs at CAN base ID 0x420 */
267 setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &fi, sizeof(struct can_filter));
273 int main(int argc, char **argv)
280 printf("syntax: %s IFNAME\n", argv[0]);
284 nm = nm_alloc(5, 0x0b, 0x420);
286 printf("Out of memory allocating NM struct.\n");
290 s = net_init(argv[1]);
292 /* Stir up the hornet's nest */
294 struct can_frame frame;
296 nm_start(nm, &frame);
306 retval = select(s+1, &rdfs, NULL, NULL, &nm->tv);
307 /* We currently rely on Linux timeout behavior here,
308 * i.e. the timeout now reflects the remaining time */
312 } else if (!retval) {
313 /* Timeout, we NEED to check this first */
314 struct can_frame frame;
316 nm_timeout_callback(nm, &frame);
318 } else if (FD_ISSET(s, &rdfs)) {
319 struct can_frame frame;
322 ret = read(s, &frame, sizeof(frame));
324 perror("recvfrom CAN socket");
328 nm_handle_can_frame(nm, &frame);