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can-utils/cangw.c

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/*
* $Id$
*/
/*
* cangw.c - manage PF_CAN netlink gateway
*
* Copyright (c) 2010 Volkswagen Group Electronic Research
* 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. Neither the name of Volkswagen nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
* The provided data structures and external interfaces from this code
* are not restricted to be used by modules with a GPL compatible license.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* OWNER 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.
*
* Send feedback to <socketcan-users@lists.berlios.de>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <libgen.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <net/if.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/can/gw.h>
enum {
UNSPEC,
ADD,
DEL,
FLUSH,
LIST
};
struct modattr {
struct can_frame cf;
__u8 modtype;
__u8 instruction;
} __attribute__((packed));
/* some netlink helpers stolen from iproute2 package */
#define NLMSG_TAIL(nmsg) \
((struct rtattr *)(((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
int alen)
{
int len = RTA_LENGTH(alen);
struct rtattr *rta;
if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
fprintf(stderr, "addattr_l: message exceeded bound of %d\n",
maxlen);
return -1;
}
rta = NLMSG_TAIL(n);
rta->rta_type = type;
rta->rta_len = len;
memcpy(RTA_DATA(rta), data, alen);
n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
return 0;
}
void printfilter(const void *data)
{
struct can_filter *filter = (struct can_filter *)data;
printf("-f %03X:%X ", filter->can_id, filter->can_mask);
}
void printmod(const char *type, const void *data)
{
struct modattr mod;
int i;
memcpy (&mod, data, CGW_MODATTR_LEN);
printf("-m %s:", type);
if (mod.modtype & CGW_MOD_ID)
printf("I");
if (mod.modtype & CGW_MOD_DLC)
printf("L");
if (mod.modtype & CGW_MOD_DATA)
printf("D");
printf(":%03X.%X.", mod.cf.can_id, mod.cf.can_dlc);
for (i = 0; i < 8; i++)
printf("%02X", mod.cf.data[i]);
printf(" ");
}
void print_usage(char *prg)
{
fprintf(stderr, "\nUsage: %s [options]\n\n", prg);
fprintf(stderr, "Commands: -A (add a new rule)\n");
fprintf(stderr, " -D (delete a rule)\n");
fprintf(stderr, " -F (flush - delete all rules) [not yet implemented]\n");
fprintf(stderr, " -L (list all rules)\n");
fprintf(stderr, "Mandatory: -s <src_dev> (source netdevice)\n");
fprintf(stderr, " -d <dst_dev> (destination netdevice)\n");
fprintf(stderr, "Options: -t (preserve src_dev rx timestamp)\n");
fprintf(stderr, " -e (echo sent frames - recommended on vcanx)\n");
fprintf(stderr, " -f <filter> (set CAN filter)\n");
fprintf(stderr, " -m <mod> (set frame modifications)\n");
fprintf(stderr, "\nValues are given and expected in hexadecimal values. Leading 0s can be omitted.\n");
fprintf(stderr, "\n");
fprintf(stderr, "<filter> is a <value>:<mask> CAN identifier filter\n");
fprintf(stderr, "\n");
fprintf(stderr, "<mod> is a CAN frame modification instruction consisting of\n");
fprintf(stderr, "<instruction>:<can_frame-elements>:<can_id>.<can_dlc>.<can_data>\n");
fprintf(stderr, " - <instruction> is one of 'AND' 'OR' 'XOR' 'SET'\n");
fprintf(stderr, " - <can_frame-elements> is _one_ or _more_ of 'I'dentifier 'L'ength 'D'ata\n");
fprintf(stderr, " - <can_id> is an u32 value containing the CAN Identifier\n");
fprintf(stderr, " - <can_dlc> is an u8 value containing the data length code (0 .. 8)\n");
fprintf(stderr, " - <can_data> is always eight(!) u8 values containing the CAN frames data\n");
fprintf(stderr, "The instructions are performed in the order 'AND' -> 'OR' -> 'XOR' -> 'SET'\n");
fprintf(stderr, "\n");
fprintf(stderr, "Example:\n");
fprintf(stderr, "%s -A -s can0 -d vcan3 -f 123:C00007FF -m SET:IL:80000333.4.1122334455667788\n", prg);
fprintf(stderr, "\n");
}
int parse_mod(char *optarg, struct modattr *modmsg)
{
char *ptr, *nptr;
int i;
char hexdata[17] = {0};
ptr = optarg;
nptr = strchr(ptr, ':');
if ((nptr - ptr > 3) || (nptr - ptr == 0))
return 1;
if (!strncmp(ptr, "AND", 3))
modmsg->instruction = CGW_MOD_AND;
else if (!strncmp(ptr, "OR", 2))
modmsg->instruction = CGW_MOD_OR;
else if (!strncmp(ptr, "XOR", 3))
modmsg->instruction = CGW_MOD_XOR;
else if (!strncmp(ptr, "SET", 3))
modmsg->instruction = CGW_MOD_SET;
else
return 2;
ptr = nptr+1;
nptr = strchr(ptr, ':');
if ((nptr - ptr > 3) || (nptr - ptr == 0))
return 3;
modmsg->modtype = 0;
while (*ptr != ':') {
switch (*ptr) {
case 'I':
modmsg->modtype |= CGW_MOD_ID;
break;
case 'L':
modmsg->modtype |= CGW_MOD_DLC;
break;
case 'D':
modmsg->modtype |= CGW_MOD_DATA;
break;
default:
return 4;
}
ptr++;
}
if ((sscanf(++ptr, "%lx.%hhd.%16s",
(long unsigned int *)&modmsg->cf.can_id,
(unsigned char *)&modmsg->cf.can_dlc, hexdata) != 3) ||
(modmsg->cf.can_dlc > 8))
return 5;
if (strlen(hexdata) != 16)
return 6;
for (i = 0; i < 8; i++) {
if (!sscanf(&hexdata[i*2], "%2hhx", &modmsg->cf.data[i]))
return 7;
}
return 0; /* ok */
}
int main(int argc, char **argv)
{
int s;
int err = 0;
int opt;
extern int optind, opterr, optopt;
int cmd = UNSPEC;
int have_filter = 0;
struct {
struct nlmsghdr nh;
struct rtcanmsg rtcan;
char buf[200];
} req;
char rxbuf[8192]; /* netlink receive buffer */
char ifname[IF_NAMESIZE]; /* internface name for if_indextoname() */
struct nlmsghdr *nlh;
struct nlmsgerr *rte;
struct rtcanmsg *rtc;
struct rtattr *rta;
__u32 handled = 0;
__u32 dropped = 0;
int rtlen;
int len;
struct can_filter filter;
struct sockaddr_nl nladdr;
struct modattr modmsg[CGW_MOD_FUNCS];
int modidx = 0;
int i;
memset(&req, 0, sizeof(req));
while ((opt = getopt(argc, argv, "ADFLs:d:tef:m:?")) != -1) {
switch (opt) {
case 'A':
if (cmd == UNSPEC)
cmd = ADD;
break;
case 'D':
if (cmd == UNSPEC)
cmd = DEL;
break;
case 'F':
if (cmd == UNSPEC)
cmd = FLUSH;
break;
case 'L':
if (cmd == UNSPEC)
cmd = LIST;
break;
case 's':
req.rtcan.src_ifindex = if_nametoindex(optarg);
break;
case 'd':
req.rtcan.dst_ifindex = if_nametoindex(optarg);
break;
case 't':
req.rtcan.can_txflags |= CAN_GW_TXFLAGS_SRC_TSTAMP;
break;
case 'e':
req.rtcan.can_txflags |= CAN_GW_TXFLAGS_ECHO;
break;
case 'f':
if (sscanf(optarg, "%lx:%lx",
(long unsigned int *)&filter.can_id,
(long unsigned int *)&filter.can_mask) == 2) {
have_filter = 1;
} else {
printf("Bad filter definition '%s'.\n", optarg);
exit(1);
}
break;
case 'm':
/* may be triggered by each of the CGW_MOD_FUNCS functions */
if ((modidx < CGW_MOD_FUNCS) && (err = parse_mod(optarg, &modmsg[modidx++]))) {
printf("Problem %d with modification definition '%s'.\n", err, optarg);
exit(1);
}
break;
case '?':
print_usage(basename(argv[0]));
exit(0);
break;
default:
fprintf(stderr, "Unknown option %c\n", opt);
print_usage(basename(argv[0]));
exit(1);
break;
}
}
if ((argc - optind != 0) || (cmd == UNSPEC)) {
print_usage(basename(argv[0]));
exit(1);
}
if ((cmd == ADD || cmd == DEL) &&
((!req.rtcan.src_ifindex) || (!req.rtcan.dst_ifindex))) {
print_usage(basename(argv[0]));
exit(1);
}
s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
switch (cmd) {
case ADD:
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.nh.nlmsg_type = RTM_NEWROUTE;
break;
case DEL:
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.nh.nlmsg_type = RTM_DELROUTE;
break;
case LIST:
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
req.nh.nlmsg_type = RTM_GETROUTE;
break;
default:
printf("This function is not yet implemented.\n");
exit(1);
break;
}
req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtcanmsg));
req.nh.nlmsg_seq = 0;
req.rtcan.can_family = AF_CAN;
/* add new attributes here */
if (have_filter)
addattr_l(&req.nh, sizeof(req), CGW_FILTER, &filter, sizeof(filter));
/*
* a better example code
* modmsg.modtype = CGW_MOD_ID;
* addattr_l(&req.n, sizeof(req), CGW_MOD_SET, &modmsg, CGW_MODATTR_LEN);
*/
/* add up to CGW_MOD_FUNCS modification definitions */
for (i = 0; i < modidx; i++)
addattr_l(&req.nh, sizeof(req), modmsg[i].instruction, &modmsg[i], CGW_MODATTR_LEN);
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = 0;
nladdr.nl_groups = 0;
err = sendto(s, &req, req.nh.nlmsg_len, 0,
(struct sockaddr*)&nladdr, sizeof(nladdr));
if (err < 0) {
perror("netlink sendto");
return err;
}
/* clean netlink receive buffer */
bzero(rxbuf, sizeof(rxbuf));
if (cmd == ADD || cmd == DEL) {
err = recv(s, &rxbuf, sizeof(rxbuf), 0);
if (err < 0) {
perror("netlink recv");
return err;
}
nlh = (struct nlmsghdr *)rxbuf;
if (nlh->nlmsg_type != NLMSG_ERROR) {
fprintf(stderr, "unexpected netlink answer of type %d\n", nlh->nlmsg_type);
return -EINVAL;
}
rte = (struct nlmsgerr *)NLMSG_DATA(nlh);
err = rte->error;
if (err < 0)
fprintf(stderr, "netlink error %d (%s)\n", err, strerror(abs(err)));
} else {
/* cmd == LIST (for now) */
while (1) {
len = recv(s, &rxbuf, sizeof(rxbuf), 0);
if (len < 0) {
perror("netlink recv");
return len;
}
nlh = (struct nlmsghdr *)rxbuf;
if (nlh->nlmsg_type == NLMSG_DONE)
break;
rtc = (struct rtcanmsg *)NLMSG_DATA(nlh);
if (rtc->can_family != AF_CAN) {
printf("received msg from unknown family %d\n", rtc->can_family);
return -EINVAL;
}
/*
* print list in a representation that
* can be used directly for start scripts
*/
printf("%s -A ", basename(argv[0]));
printf("-s %s ", if_indextoname(rtc->src_ifindex, ifname));
printf("-d %s ", if_indextoname(rtc->dst_ifindex, ifname));
if (rtc->can_txflags & CAN_GW_TXFLAGS_ECHO)
printf("-e ");
if (rtc->can_txflags & CAN_GW_TXFLAGS_SRC_TSTAMP)
printf("-t ");
/* check for attributes */
rta = (struct rtattr *) RTM_RTA(rtc);
rtlen = RTM_PAYLOAD(nlh);
for(;RTA_OK(rta, rtlen);rta=RTA_NEXT(rta,rtlen))
{
switch(rta->rta_type) {
case CGW_FILTER:
printfilter(RTA_DATA(rta));
break;
case CGW_MOD_AND:
printmod("AND", RTA_DATA(rta));
break;
case CGW_MOD_OR:
printmod("OR", RTA_DATA(rta));
break;
case CGW_MOD_XOR:
printmod("XOR", RTA_DATA(rta));
break;
case CGW_MOD_SET:
printmod("SET", RTA_DATA(rta));
break;
case CGW_HANDLED:
handled = *(__u32 *)RTA_DATA(rta);
break;
case CGW_DROPPED:
dropped = *(__u32 *)RTA_DATA(rta);
break;
default:
printf("Unknown attribute %d!", rta->rta_type);
return -EINVAL;
break;
}
}
printf("# %d handled %d dropped\n", handled, dropped); /* end of entry */
}
}
close(s);
return err;
}
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