cangw: add an option for the per rule limitation of frame hops

Usually the received CAN frames can be processed/routed as much as 'max_hops'
times (which is given at module load time of the can-gw module).
Introduce a new configuration option ( -l <hops> ) to reduce the number of
possible hops for a specific gateway rule to a value smaller then max_hops.

Mainline upstream commit:

http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=391ac1282dd7ff1cb8245cccc5262e8e4173edc4

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
pull/1/head
Oliver Hartkopp 2013-09-04 20:30:34 +02:00
parent 93ef3b1d81
commit ad7f44095a
2 changed files with 26 additions and 2 deletions

19
cangw.c
View File

@ -196,6 +196,7 @@ void print_usage(char *prg)
fprintf(stderr, "Options: -t (preserve src_dev rx timestamp)\n");
fprintf(stderr, " -e (echo sent frames - recommended on vcanx)\n");
fprintf(stderr, " -i (allow to route to incoming interface)\n");
fprintf(stderr, " -l <hops> (limit the number of frame hops / routings)\n");
fprintf(stderr, " -f <filter> (set CAN filter)\n");
fprintf(stderr, " -m <mod> (set frame modifications)\n");
fprintf(stderr, " -x <from_idx>:<to_idx>:<result_idx>:<init_xor_val> (XOR checksum)\n");
@ -417,6 +418,7 @@ int parse_rtlist(char *prgname, unsigned char *rxbuf, int len)
case CGW_MOD_OR:
case CGW_MOD_XOR:
case CGW_MOD_SET:
case CGW_LIM_HOPS:
case CGW_CS_XOR:
case CGW_CS_CRC8:
break;
@ -489,6 +491,10 @@ int parse_rtlist(char *prgname, unsigned char *rxbuf, int len)
printmod("SET", RTA_DATA(rta));
break;
case CGW_LIM_HOPS:
printf("-l %d ", *(__u8 *)RTA_DATA(rta));
break;
case CGW_CS_XOR:
print_cs_xor((struct cgw_csum_xor *)RTA_DATA(rta));
break;
@ -545,6 +551,7 @@ int main(int argc, char **argv)
struct nlmsgerr *rte;
unsigned int src_ifindex = 0;
unsigned int dst_ifindex = 0;
__u8 limit_hops = 0;
__u16 flags = 0;
int len;
@ -563,7 +570,7 @@ int main(int argc, char **argv)
memset(&cs_xor, 0, sizeof(cs_xor));
memset(&cs_crc8, 0, sizeof(cs_crc8));
while ((opt = getopt(argc, argv, "ADFLs:d:teif:c:p:x:m:?")) != -1) {
while ((opt = getopt(argc, argv, "ADFLs:d:teil:f:c:p:x:m:?")) != -1) {
switch (opt) {
case 'A':
@ -606,6 +613,13 @@ int main(int argc, char **argv)
flags |= CGW_FLAGS_CAN_IIF_TX_OK;
break;
case 'l':
if (sscanf(optarg, "%hhd", &limit_hops) != 1 || !(limit_hops)) {
printf("Bad hop limit definition '%s'.\n", optarg);
exit(1);
}
break;
case 'f':
if (sscanf(optarg, "%x:%x", &filter.can_id,
&filter.can_mask) == 2) {
@ -743,6 +757,9 @@ int main(int argc, char **argv)
if (have_cs_xor)
addattr_l(&req.nh, sizeof(req), CGW_CS_XOR, &cs_xor, sizeof(cs_xor));
if (limit_hops)
addattr_l(&req.nh, sizeof(req), CGW_LIM_HOPS, &limit_hops, sizeof(__u8));
/*
* a better example code
* modmsg.modtype = CGW_MOD_ID;

View File

@ -45,6 +45,7 @@ enum {
CGW_DST_IF, /* ifindex of destination network interface */
CGW_FILTER, /* specify struct can_filter on source CAN device */
CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */
CGW_LIM_HOPS, /* limit the number of hops of this specific rule */
__CGW_MAX
};
@ -116,13 +117,19 @@ enum {
* Sets a CAN receive filter for the gateway job specified by the
* struct can_filter described in include/linux/can.h
*
* CGW_MOD_XXX (length 17 bytes):
* CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes):
* Specifies a modification that's done to a received CAN frame before it is
* send out to the destination interface.
*
* <struct can_frame> data used as operator
* <u8> affected CAN frame elements
*
* CGW_LIM_HOPS (length 1 byte):
* Limit the number of hops of this specific rule. Usually the received CAN
* frame can be processed as much as 'max_hops' times (which is given at module
* load time of the can-gw module). This value is used to reduce the number of
* possible hops for this gateway job to a value smaller then max_hops.
*
* CGW_CS_XOR (length 4 bytes):
* Set a simple XOR checksum starting with an initial value into
* data[result-idx] using data[start-idx] .. data[end-idx]