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cangen: auto mix of CC/FD/XL frames #608

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Merged
hartkopp merged 2 commits into from
Dec 3, 2025
Merged

cangen: auto mix of CC/FD/XL frames #608

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0ab7182
cangen: auto enable FD/XL content in mixed mode
hartkopp Sep 8, 2025
af328b8
cangen: disable generation of unsupported CAN frame types in mixed mode
hartkopp Nov 27, 2025
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158 changes: 107 additions & 51 deletions cangen.c
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Original file line number Diff line number Diff line change
Expand Up @@ -180,7 +180,7 @@ static void print_usage(char *prg)
fprintf(stderr, " -X (generate CAN XL CAN frames)\n");
fprintf(stderr, " -R (generate RTR frames)\n");
fprintf(stderr, " -8 (allow DLC values greater then 8 for Classic CAN frames)\n");
fprintf(stderr, " -m (mix -e -f -b -E -R -X frames)\n");
fprintf(stderr, " -m (mix CC [-e -R] FD [-f -b -E] XL [-X] on capable devices)\n");
fprintf(stderr, " -I <mode> (CAN ID generation mode - see below)\n");
fprintf(stderr, " -L <mode> (CAN data length code (dlc) generation mode - see below)\n");
fprintf(stderr, " -D <mode> (CAN data (payload) generation mode - see below)\n");
Expand Down Expand Up @@ -339,10 +339,9 @@ static int do_send_one(int fd, cu_t *cu, size_t len, int timeout)
nbytes = sendmsg(fd, &msg, 0);
if (nbytes < 0) {
ret = -errno;
if (ret != -ENOBUFS) {
perror("write");
if (ret != -ENOBUFS)
return ret;
}

if (!ignore_enobufs && !timeout) {
perror("write");
return ret;
Expand Down Expand Up @@ -455,6 +454,9 @@ int main(int argc, char **argv)
unsigned char extended = 0;
unsigned char canfd = 0;
unsigned char canxl = 0;
unsigned char mixcc = 1; /* mix default */
unsigned char mixfd = 1; /* mix default */
unsigned char mixxl = 1; /* mix default */
unsigned char brs = 0;
unsigned char esi = 0;
unsigned char mix = 0;
Expand Down Expand Up @@ -574,7 +576,6 @@ int main(int argc, char **argv)

case 'm':
mix = 1;
canfd = 1; /* to switch the socket into CAN FD mode */
view |= CANLIB_VIEW_INDENT_SFF;
break;

Expand Down Expand Up @@ -777,57 +778,66 @@ int main(int argc, char **argv)
&loopback, sizeof(loopback));
}

if (canfd || canxl) {
/* get CAN netdevice MTU for frame type capabilities */
if (ioctl(s, SIOCGIFMTU, &ifr) < 0) {
perror("SIOCGIFMTU");
return 1;
}

/* check if the frame fits into the CAN netdevice */
if (ioctl(s, SIOCGIFMTU, &ifr) < 0) {
perror("SIOCGIFMTU");
/* check CAN XL support */
if (ifr.ifr_mtu < (int)CANXL_MIN_MTU) {
mixxl = 0;
if (canxl) {
printf("CAN interface not CAN XL capable - sorry.\n");
return 1;
}
}

/* check CAN FD support */
if (ifr.ifr_mtu < (int)CANFD_MTU) {
mixfd = 0;
if (canfd) {
/* ensure discrete CAN FD length values 0..8, 12, 16, 20, 24, 32, 64 */
cu.fd.len = can_fd_dlc2len(can_fd_len2dlc(cu.fd.len));
} else {
/* limit fixed CAN XL data length to 64 */
if (cu.fd.len > CANFD_MAX_DLEN)
cu.fd.len = CANFD_MAX_DLEN;
printf("CAN interface not CAN FD capable - sorry.\n");
return 1;
}
}

if (canxl && (ifr.ifr_mtu < (int)CANXL_MIN_MTU)) {
printf("CAN interface not CAN XL capable - sorry.\n");
/* enable CAN FD on the socket */
if (mixfd) {
/* interface is ok - try to switch the socket into CAN FD mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_FD_FRAMES,
&enable_canfx, sizeof(enable_canfx))){
printf("error when enabling CAN FD support\n");
return 1;
}
}

if (canfd && (ifr.ifr_mtu < (int)CANFD_MTU)) {
printf("CAN interface not CAN FD capable - sorry.\n");
/* enable CAN XL on the socket */
if (mixxl) {
/* interface is ok - try to switch the socket into CAN XL mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_XL_FRAMES,
&enable_canfx, sizeof(enable_canfx))){
printf("error when enabling CAN XL support\n");
return 1;
}

if (ifr.ifr_mtu == (int)CANFD_MTU) {
/* interface is ok - try to switch the socket into CAN FD mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_FD_FRAMES,
&enable_canfx, sizeof(enable_canfx))){
printf("error when enabling CAN FD support\n");
return 1;
}
/* try to enable the CAN XL VCID pass through mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_XL_VCID_OPTS,
&vcid_opts, sizeof(vcid_opts))) {
printf("error when enabling CAN XL VCID pass through\n");
return 1;
}
}

if (ifr.ifr_mtu >= (int)CANXL_MIN_MTU) {
/* interface is ok - try to switch the socket into CAN XL mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_XL_FRAMES,
&enable_canfx, sizeof(enable_canfx))){
printf("error when enabling CAN XL support\n");
return 1;
}
/* try to enable the CAN XL VCID pass through mode */
if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_XL_VCID_OPTS,
&vcid_opts, sizeof(vcid_opts))) {
printf("error when enabling CAN XL VCID pass through\n");
return 1;
}
/* sanitize given values */
if (canfd || canxl) {
if (canfd) {
/* ensure discrete CAN FD length values 0..8, 12, 16, 20, 24, 32, 64 */
cu.fd.len = can_fd_dlc2len(can_fd_len2dlc(cu.fd.len));
} else {
/* limit fixed CAN XL data length to 64 */
if (cu.fd.len > CANFD_MAX_DLEN)
cu.fd.len = CANFD_MAX_DLEN;
}

} else {
/* sanitize Classical CAN 2.0 frame length */
if (len8_dlc) {
Expand Down Expand Up @@ -1040,8 +1050,31 @@ int main(int argc, char **argv)
}

ret = do_send_one(s, &cu, mtu, polltimeout);
if (ret)
if ((ret == -EINVAL) && mix) {
/* mix mode: disable unsupported CAN frame type */
switch (mtu) {
case CAN_MTU:
mixcc = 0;
break;
case CANFD_MTU:
mixfd = 0;
break;
case CANXL_MTU:
mixxl = 0;
break;
default:
printf ("mix mode: unknown MTU");
return 1;
}
if (!mixcc && !mixfd && !mixxl) {
printf ("mix mode: no valid CAN frame types\n");
return 1;
}
} else if (ret) {
/* other error than -ENOBUFS and -EINVAL */
perror("write");
return 1;
}

if (burst_sent_count >= burst_count)
burst_sent_count = 0;
Expand Down Expand Up @@ -1082,18 +1115,41 @@ int main(int argc, char **argv)
}

if (mix) {
canfd = 0;
canxl = 0;
i = random();
extended = i & 1;
canfd = i & 2;
if (canfd) {
brs = i & 4;
esi = i & 8;
if (mixfd) {
canfd = i & 2;
if (canfd) {
brs = i & 4;
esi = i & 8;
}
}
if (mixxl) {
if (mixfd)
canxl = ((i & 96) == 96); /* 1/4 */
else
canxl = ((i & 32) == 32); /* 1/2 */
}
if (mixcc) {
rtr_frame = ((i & 24) == 24); /* reduce RTR to 1/4 */
} else {
/* no CC frames allowed - CAN XL-only mode? */
if (!canxl && !canfd) {
/* force XL or FD frames */
if (mixxl)
canxl = 1;
else if (mixfd) {
canfd = 1;
brs = i & 4;
esi = i & 8;
} else {
printf ("mix mode: no valid CAN frame types\n");
return 1;
}
}
}
/* generate CAN XL traffic if the interface is capable */
if (ifr.ifr_mtu >= (int)CANXL_MIN_MTU)
canxl = ((i & 96) == 96);

rtr_frame = ((i & 24) == 24); /* reduce RTR frames to 1/4 */
}
}

Expand Down
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