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selftests: mptcp: capture netlink events
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This change adds to self-testing support for the MPTCP netlink interface
by capturing various MPTCP netlink events (and all their metadata)
associated with connections, subflows and address announcements.
It is used in self-testing scripts that exercise MPTCP netlink commands
to precisely validate those operations by examining the dispatched
MPTCP netlink events in response to those commands.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Kishen Maloor authored and David S. Miller committed May 4, 2022
1 parent 57cc361 commit b3e5fd6
Showing 1 changed file with 157 additions and 7 deletions.
164 changes: 157 additions & 7 deletions tools/testing/selftests/net/mptcp/pm_nl_ctl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,9 @@
#ifndef MPTCP_PM_NAME
#define MPTCP_PM_NAME "mptcp_pm"
#endif
#ifndef MPTCP_PM_EVENTS
#define MPTCP_PM_EVENTS "mptcp_pm_events"
#endif

static void syntax(char *argv[])
{
Expand All @@ -37,6 +40,7 @@ static void syntax(char *argv[])
fprintf(stderr, "\tflush\n");
fprintf(stderr, "\tdump\n");
fprintf(stderr, "\tlimits [<rcv addr max> <subflow max>]\n");
fprintf(stderr, "\tevents\n");
exit(0);
}

Expand Down Expand Up @@ -88,6 +92,108 @@ static void nl_error(struct nlmsghdr *nh)
}
}

static int capture_events(int fd, int event_group)
{
u_int8_t buffer[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct genlmsghdr)) + 1024];
struct genlmsghdr *ghdr;
struct rtattr *attrs;
struct nlmsghdr *nh;
int ret = 0;
int res_len;
int msg_len;
fd_set rfds;

if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
&event_group, sizeof(event_group)) < 0)
error(1, errno, "could not join the " MPTCP_PM_EVENTS " mcast group");

do {
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
res_len = NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct genlmsghdr)) + 1024;

ret = select(FD_SETSIZE, &rfds, NULL, NULL, NULL);

if (ret < 0)
error(1, ret, "error in select() on NL socket");

res_len = recv(fd, buffer, res_len, 0);
if (res_len < 0)
error(1, res_len, "error on recv() from NL socket");

nh = (struct nlmsghdr *)buffer;

for (; NLMSG_OK(nh, res_len); nh = NLMSG_NEXT(nh, res_len)) {
if (nh->nlmsg_type == NLMSG_ERROR)
error(1, NLMSG_ERROR, "received invalid NL message");

ghdr = (struct genlmsghdr *)NLMSG_DATA(nh);

if (ghdr->cmd == 0)
continue;

fprintf(stderr, "type:%d", ghdr->cmd);

msg_len = nh->nlmsg_len - NLMSG_LENGTH(GENL_HDRLEN);

attrs = (struct rtattr *) ((char *) ghdr + GENL_HDRLEN);
while (RTA_OK(attrs, msg_len)) {
if (attrs->rta_type == MPTCP_ATTR_TOKEN)
fprintf(stderr, ",token:%u", *(__u32 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_FAMILY)
fprintf(stderr, ",family:%u", *(__u16 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_LOC_ID)
fprintf(stderr, ",loc_id:%u", *(__u8 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_REM_ID)
fprintf(stderr, ",rem_id:%u", *(__u8 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_SADDR4) {
u_int32_t saddr4 = ntohl(*(__u32 *)RTA_DATA(attrs));

fprintf(stderr, ",saddr4:%u.%u.%u.%u", saddr4 >> 24,
(saddr4 >> 16) & 0xFF, (saddr4 >> 8) & 0xFF,
(saddr4 & 0xFF));
} else if (attrs->rta_type == MPTCP_ATTR_SADDR6) {
char buf[INET6_ADDRSTRLEN];

if (inet_ntop(AF_INET6, RTA_DATA(attrs), buf,
sizeof(buf)) != NULL)
fprintf(stderr, ",saddr6:%s", buf);
} else if (attrs->rta_type == MPTCP_ATTR_DADDR4) {
u_int32_t daddr4 = ntohl(*(__u32 *)RTA_DATA(attrs));

fprintf(stderr, ",daddr4:%u.%u.%u.%u", daddr4 >> 24,
(daddr4 >> 16) & 0xFF, (daddr4 >> 8) & 0xFF,
(daddr4 & 0xFF));
} else if (attrs->rta_type == MPTCP_ATTR_DADDR6) {
char buf[INET6_ADDRSTRLEN];

if (inet_ntop(AF_INET6, RTA_DATA(attrs), buf,
sizeof(buf)) != NULL)
fprintf(stderr, ",daddr6:%s", buf);
} else if (attrs->rta_type == MPTCP_ATTR_SPORT)
fprintf(stderr, ",sport:%u",
ntohs(*(__u16 *)RTA_DATA(attrs)));
else if (attrs->rta_type == MPTCP_ATTR_DPORT)
fprintf(stderr, ",dport:%u",
ntohs(*(__u16 *)RTA_DATA(attrs)));
else if (attrs->rta_type == MPTCP_ATTR_BACKUP)
fprintf(stderr, ",backup:%u", *(__u8 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_ERROR)
fprintf(stderr, ",error:%u", *(__u8 *)RTA_DATA(attrs));
else if (attrs->rta_type == MPTCP_ATTR_SERVER_SIDE)
fprintf(stderr, ",server_side:%u", *(__u8 *)RTA_DATA(attrs));

attrs = RTA_NEXT(attrs, msg_len);
}
}
fprintf(stderr, "\n");
} while (1);

return 0;
}

/* do a netlink command and, if max > 0, fetch the reply */
static int do_nl_req(int fd, struct nlmsghdr *nh, int len, int max)
{
Expand Down Expand Up @@ -121,11 +227,18 @@ static int do_nl_req(int fd, struct nlmsghdr *nh, int len, int max)
return ret;
}

static int genl_parse_getfamily(struct nlmsghdr *nlh)
static int genl_parse_getfamily(struct nlmsghdr *nlh, int *pm_family,
int *events_mcast_grp)
{
struct genlmsghdr *ghdr = NLMSG_DATA(nlh);
int len = nlh->nlmsg_len;
struct rtattr *attrs;
struct rtattr *grps;
struct rtattr *grp;
int got_events_grp;
int got_family;
int grps_len;
int grp_len;

if (nlh->nlmsg_type != GENL_ID_CTRL)
error(1, errno, "Not a controller message, len=%d type=0x%x\n",
Expand All @@ -140,17 +253,50 @@ static int genl_parse_getfamily(struct nlmsghdr *nlh)
error(1, errno, "Unknown controller command %d\n", ghdr->cmd);

attrs = (struct rtattr *) ((char *) ghdr + GENL_HDRLEN);
got_family = 0;
got_events_grp = 0;

while (RTA_OK(attrs, len)) {
if (attrs->rta_type == CTRL_ATTR_FAMILY_ID)
return *(__u16 *)RTA_DATA(attrs);
if (attrs->rta_type == CTRL_ATTR_FAMILY_ID) {
*pm_family = *(__u16 *)RTA_DATA(attrs);
got_family = 1;
} else if (attrs->rta_type == CTRL_ATTR_MCAST_GROUPS) {
grps = RTA_DATA(attrs);
grps_len = RTA_PAYLOAD(attrs);

while (RTA_OK(grps, grps_len)) {
grp = RTA_DATA(grps);
grp_len = RTA_PAYLOAD(grps);
got_events_grp = 0;

while (RTA_OK(grp, grp_len)) {
if (grp->rta_type == CTRL_ATTR_MCAST_GRP_ID)
*events_mcast_grp = *(__u32 *)RTA_DATA(grp);
else if (grp->rta_type == CTRL_ATTR_MCAST_GRP_NAME &&
!strcmp(RTA_DATA(grp), MPTCP_PM_EVENTS))
got_events_grp = 1;

grp = RTA_NEXT(grp, grp_len);
}

if (got_events_grp)
break;

grps = RTA_NEXT(grps, grps_len);
}
}

if (got_family && got_events_grp)
return 0;

attrs = RTA_NEXT(attrs, len);
}

error(1, errno, "can't find CTRL_ATTR_FAMILY_ID attr");
return -1;
}

static int resolve_mptcp_pm_netlink(int fd)
static int resolve_mptcp_pm_netlink(int fd, int *pm_family, int *events_mcast_grp)
{
char data[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct genlmsghdr)) +
Expand All @@ -172,7 +318,7 @@ static int resolve_mptcp_pm_netlink(int fd)
off += NLMSG_ALIGN(rta->rta_len);

do_nl_req(fd, nh, off, sizeof(data));
return genl_parse_getfamily((void *)data);
return genl_parse_getfamily((void *)data, pm_family, events_mcast_grp);
}

int dsf(int fd, int pm_family, int argc, char *argv[])
Expand Down Expand Up @@ -1192,7 +1338,9 @@ int set_flags(int fd, int pm_family, int argc, char *argv[])

int main(int argc, char *argv[])
{
int fd, pm_family;
int events_mcast_grp;
int pm_family;
int fd;

if (argc < 2)
syntax(argv);
Expand All @@ -1201,7 +1349,7 @@ int main(int argc, char *argv[])
if (fd == -1)
error(1, errno, "socket netlink");

pm_family = resolve_mptcp_pm_netlink(fd);
resolve_mptcp_pm_netlink(fd, &pm_family, &events_mcast_grp);

if (!strcmp(argv[1], "add"))
return add_addr(fd, pm_family, argc, argv);
Expand All @@ -1225,6 +1373,8 @@ int main(int argc, char *argv[])
return get_set_limits(fd, pm_family, argc, argv);
else if (!strcmp(argv[1], "set"))
return set_flags(fd, pm_family, argc, argv);
else if (!strcmp(argv[1], "events"))
return capture_events(fd, events_mcast_grp);

fprintf(stderr, "unknown sub-command: %s", argv[1]);
syntax(argv);
Expand Down

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