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samples/bpf: Check the prog id before exiting
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Check the program id within the signal handler on polling xdp samples
that were previously converted to libbpf usage. Avoid the situation of
unloading the program that was not attached by sample that is exiting.
Handle also the case where bpf_get_link_xdp_id didn't exit with an error
but the xdp program was not found on an interface.

Reported-by: Michal Papaj <michal.papaj@intel.com>
Reported-by: Jakub Spizewski <jakub.spizewski@intel.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Maciej Fijalkowski authored and Daniel Borkmann committed Feb 1, 2019
1 parent 50db9f0 commit 3b7a8ec
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Showing 10 changed files with 308 additions and 48 deletions.
24 changes: 23 additions & 1 deletion samples/bpf/xdp1_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,10 +23,22 @@

static int ifindex;
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static __u32 prog_id;

static void int_exit(int sig)
{
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
__u32 curr_prog_id = 0;

if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on a given interface\n");
else
printf("program on interface changed, not removing\n");
exit(0);
}

Expand Down Expand Up @@ -74,11 +86,14 @@ int main(int argc, char **argv)
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_XDP,
};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const char *optstr = "FSN";
int prog_fd, map_fd, opt;
struct bpf_object *obj;
struct bpf_map *map;
char filename[256];
int err;

while ((opt = getopt(argc, argv, optstr)) != -1) {
switch (opt) {
Expand Down Expand Up @@ -139,6 +154,13 @@ int main(int argc, char **argv)
return 1;
}

err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (err) {
printf("can't get prog info - %s\n", strerror(errno));
return err;
}
prog_id = info.id;

poll_stats(map_fd, 2);

return 0;
Expand Down
30 changes: 26 additions & 4 deletions samples/bpf/xdp_adjust_tail_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,24 @@

static int ifindex = -1;
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static __u32 prog_id;

static void int_exit(int sig)
{
if (ifindex > -1)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
__u32 curr_prog_id = 0;

if (ifindex > -1) {
if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on a given iface\n");
else
printf("program on interface changed, not removing\n");
}
exit(0);
}

Expand Down Expand Up @@ -72,11 +85,14 @@ int main(int argc, char **argv)
};
unsigned char opt_flags[256] = {};
const char *optstr = "i:T:SNFh";
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
unsigned int kill_after_s = 0;
int i, prog_fd, map_fd, opt;
struct bpf_object *obj;
struct bpf_map *map;
char filename[256];
int err;

for (i = 0; i < strlen(optstr); i++)
if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
Expand Down Expand Up @@ -146,9 +162,15 @@ int main(int argc, char **argv)
return 1;
}

poll_stats(map_fd, kill_after_s);
err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (err) {
printf("can't get prog info - %s\n", strerror(errno));
return 1;
}
prog_id = info.id;

bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
poll_stats(map_fd, kill_after_s);
int_exit(0);

return 0;
}
35 changes: 29 additions & 6 deletions samples/bpf/xdp_redirect_cpu_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@ static const char *__doc__ =
static int ifindex = -1;
static char ifname_buf[IF_NAMESIZE];
static char *ifname;
static __u32 prog_id;

static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int cpu_map_fd;
Expand Down Expand Up @@ -68,11 +69,24 @@ static const struct option long_options[] = {

static void int_exit(int sig)
{
fprintf(stderr,
"Interrupted: Removing XDP program on ifindex:%d device:%s\n",
ifindex, ifname);
if (ifindex > -1)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
__u32 curr_prog_id = 0;

if (ifindex > -1) {
if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(EXIT_FAIL);
}
if (prog_id == curr_prog_id) {
fprintf(stderr,
"Interrupted: Removing XDP program on ifindex:%d device:%s\n",
ifindex, ifname);
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
} else if (!curr_prog_id) {
printf("couldn't find a prog id on a given iface\n");
} else {
printf("program on interface changed, not removing\n");
}
}
exit(EXIT_OK);
}

Expand Down Expand Up @@ -608,6 +622,8 @@ int main(int argc, char **argv)
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
bool use_separators = true;
bool stress_mode = false;
struct bpf_program *prog;
Expand All @@ -617,9 +633,9 @@ int main(int argc, char **argv)
int longindex = 0;
int interval = 2;
int add_cpu = -1;
int opt, err;
int prog_fd;
__u32 qsize;
int opt;

/* Notice: choosing he queue size is very important with the
* ixgbe driver, because it's driver page recycling trick is
Expand Down Expand Up @@ -746,6 +762,13 @@ int main(int argc, char **argv)
return EXIT_FAIL_XDP;
}

err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (err) {
printf("can't get prog info - %s\n", strerror(errno));
return err;
}
prog_id = info.id;

stats_poll(interval, use_separators, prog_name, stress_mode);
return EXIT_OK;
}
49 changes: 46 additions & 3 deletions samples/bpf/xdp_redirect_map_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,15 +29,41 @@
static int ifindex_in;
static int ifindex_out;
static bool ifindex_out_xdp_dummy_attached = true;
static __u32 prog_id;
static __u32 dummy_prog_id;

static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int rxcnt_map_fd;

static void int_exit(int sig)
{
bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
if (ifindex_out_xdp_dummy_attached)
bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
__u32 curr_prog_id = 0;

if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on iface IN\n");
else
printf("program on iface IN changed, not removing\n");

if (ifindex_out_xdp_dummy_attached) {
curr_prog_id = 0;
if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on iface OUT\n");
else
printf("program on iface OUT changed, not removing\n");
}
exit(0);
}

Expand Down Expand Up @@ -82,6 +108,8 @@ int main(int argc, char **argv)
.prog_type = BPF_PROG_TYPE_XDP,
};
struct bpf_program *prog, *dummy_prog;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
int prog_fd, dummy_prog_fd;
const char *optstr = "FSN";
struct bpf_object *obj;
Expand Down Expand Up @@ -153,13 +181,28 @@ int main(int argc, char **argv)
return 1;
}

ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (ret) {
printf("can't get prog info - %s\n", strerror(errno));
return ret;
}
prog_id = info.id;

/* Loading dummy XDP prog on out-device */
if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
(xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
ifindex_out_xdp_dummy_attached = false;
}

memset(&info, 0, sizeof(info));
ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
if (ret) {
printf("can't get prog info - %s\n", strerror(errno));
return ret;
}
dummy_prog_id = info.id;

signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);

Expand Down
49 changes: 46 additions & 3 deletions samples/bpf/xdp_redirect_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,15 +29,41 @@
static int ifindex_in;
static int ifindex_out;
static bool ifindex_out_xdp_dummy_attached = true;
static __u32 prog_id;
static __u32 dummy_prog_id;

static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int rxcnt_map_fd;

static void int_exit(int sig)
{
bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
if (ifindex_out_xdp_dummy_attached)
bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
__u32 curr_prog_id = 0;

if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on iface IN\n");
else
printf("program on iface IN changed, not removing\n");

if (ifindex_out_xdp_dummy_attached) {
curr_prog_id = 0;
if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on iface OUT\n");
else
printf("program on iface OUT changed, not removing\n");
}
exit(0);
}

Expand Down Expand Up @@ -84,6 +110,8 @@ int main(int argc, char **argv)
};
struct bpf_program *prog, *dummy_prog;
int prog_fd, tx_port_map_fd, opt;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const char *optstr = "FSN";
struct bpf_object *obj;
char filename[256];
Expand Down Expand Up @@ -154,13 +182,28 @@ int main(int argc, char **argv)
return 1;
}

ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (ret) {
printf("can't get prog info - %s\n", strerror(errno));
return ret;
}
prog_id = info.id;

/* Loading dummy XDP prog on out-device */
if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
(xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
ifindex_out_xdp_dummy_attached = false;
}

memset(&info, 0, sizeof(info));
ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (ret) {
printf("can't get prog info - %s\n", strerror(errno));
return ret;
}
dummy_prog_id = info.id;

signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);

Expand Down
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