recvmsg might not return all interface data at once. Use a non-blocking
socket and read several times until there is no more data.
Signed-off-by: Alexander Stein <alexander.st...@systec-electronic.com>
---
Not sure where exactly to put this.
src/libsocketcan.c | 247 +++++++++++++++++++++++++++-------------------------
1 files changed, 130 insertions(+), 117 deletions(-)
diff --git a/src/libsocketcan.c b/src/libsocketcan.c
index 2ac3f2a..dcdece0 100644
--- a/src/libsocketcan.c
+++ b/src/libsocketcan.c
@@ -257,6 +257,7 @@ static int open_nl_sock()
int fd;
int sndbuf = 32768;
int rcvbuf = 32768;
+ int flags;
unsigned int addr_len;
struct sockaddr_nl local;
@@ -269,6 +270,10 @@ static int open_nl_sock()
setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (void *)&sndbuf, sizeof(sndbuf));
setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (void *)&rcvbuf, sizeof(rcvbuf));
+
+ if (-1 == (flags = fcntl(fd, F_GETFL, 0)))
+ flags = 0;
+ fcntl(fd, F_SETFL, flags | O_NONBLOCK);
memset(&local, 0, sizeof(local));
local.nl_family = AF_NETLINK;
@@ -348,130 +353,138 @@ static int do_get_nl_link(int fd, __u8 acquire, const
char *name, void *res)
return ret;
}
- if ((msglen = recvmsg(fd, &msg, 0)) <= 0) {
- perror("Receive error");
- return ret;
- }
- size_t u_msglen = (size_t) msglen;
- /* Check to see if the buffers in msg get truncated */
- if (msg.msg_namelen != sizeof(peer) ||
- (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
- fprintf(stderr, "Uhoh... truncated message.\n");
- return ret;
- }
-
- for (nl_msg = (struct nlmsghdr *)nlbuf;
- NLMSG_OK(nl_msg, u_msglen);
- nl_msg = NLMSG_NEXT(nl_msg, u_msglen)) {
- int type = nl_msg->nlmsg_type;
- int len;
- if (type != RTM_NEWLINK)
- continue;
-
- struct ifinfomsg *ifi = NLMSG_DATA(nl_msg);
- struct rtattr *tb[IFLA_MAX + 1];
-
- len =
- nl_msg->nlmsg_len - NLMSG_LENGTH(sizeof(struct ifaddrmsg));
- parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
-
- if (strncmp
- ((char *)RTA_DATA(tb[IFLA_IFNAME]), name,
- sizeof(name)) != 0)
- continue;
-
- if (tb[IFLA_LINKINFO])
- parse_rtattr_nested(linkinfo,
- IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
- else
- continue;
-
- if (!linkinfo[IFLA_INFO_DATA]) {
- fprintf(stderr, "no link data found\n");
+ while ((msglen = recvmsg(fd, &msg, 0)) > 0) {
+ size_t u_msglen = (size_t) msglen;
+ /* Check to see if the buffers in msg get truncated */
+ if (msg.msg_namelen != sizeof(peer) ||
+ (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+ fprintf(stderr, "Uhoh... truncated message.\n");
return ret;
}
- parse_rtattr_nested(can_attr, IFLA_CAN_MAX,
- linkinfo[IFLA_INFO_DATA]);
-
- switch (acquire) {
- case GET_STATE:
- if (can_attr[IFLA_CAN_STATE]) {
- *((int *)res) = *((__u32 *)
- RTA_DATA(can_attr
- [IFLA_CAN_STATE]));
- ret = 0;
- } else {
- fprintf(stderr, "no state data found\n");
+ for (nl_msg = (struct nlmsghdr *)nlbuf;
+ NLMSG_OK(nl_msg, u_msglen);
+ nl_msg = NLMSG_NEXT(nl_msg, u_msglen)) {
+ int type = nl_msg->nlmsg_type;
+ int len;
+ printf("message type: %d\n", type);
+ if (type != RTM_NEWLINK)
+ continue;
+
+ struct ifinfomsg *ifi = NLMSG_DATA(nl_msg);
+ struct rtattr *tb[IFLA_MAX + 1];
+
+ printf("nl_msg->nlmsg_len: %d\n", nl_msg->nlmsg_len);
+ len =
+ nl_msg->nlmsg_len - NLMSG_LENGTH(sizeof(struct
ifaddrmsg));
+ parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
+
+ printf("do we want interface: %s\n", (char
*)RTA_DATA(tb[IFLA_IFNAME]));
+ if (strncmp
+ ((char *)RTA_DATA(tb[IFLA_IFNAME]), name,
+ sizeof(name)) != 0)
+ continue;
+
+ if (tb[IFLA_LINKINFO])
+ parse_rtattr_nested(linkinfo,
+ IFLA_INFO_MAX,
tb[IFLA_LINKINFO]);
+ else
+ continue;
+
+ if (!linkinfo[IFLA_INFO_DATA]) {
+ fprintf(stderr, "no link data found\n");
+ return ret;
}
- break;
- case GET_RESTART_MS:
- if (can_attr[IFLA_CAN_RESTART_MS]) {
- *((__u32 *) res) = *((__u32 *)
- RTA_DATA(can_attr
-
[IFLA_CAN_RESTART_MS]));
- ret = 0;
- } else
- fprintf(stderr, "no restart_ms data found\n");
-
- break;
- case GET_BITTIMING:
- if (can_attr[IFLA_CAN_BITTIMING]) {
- memcpy(res,
- RTA_DATA(can_attr[IFLA_CAN_BITTIMING]),
- sizeof(struct can_bittiming));
- ret = 0;
- } else
- fprintf(stderr, "no bittiming data found\n");
-
- break;
- case GET_CTRLMODE:
- if (can_attr[IFLA_CAN_CTRLMODE]) {
- memcpy(res,
- RTA_DATA(can_attr[IFLA_CAN_CTRLMODE]),
- sizeof(struct can_ctrlmode));
- ret = 0;
- } else
- fprintf(stderr, "no ctrlmode data found\n");
-
- break;
- case GET_CLOCK:
- if (can_attr[IFLA_CAN_CLOCK]) {
- memcpy(res,
- RTA_DATA(can_attr[IFLA_CAN_CLOCK]),
- sizeof(struct can_clock));
- ret = 0;
- } else
- fprintf(stderr,
- "no clock parameter data found\n");
-
- break;
- case GET_BITTIMING_CONST:
- if (can_attr[IFLA_CAN_BITTIMING_CONST]) {
- memcpy(res,
-
RTA_DATA(can_attr[IFLA_CAN_BITTIMING_CONST]),
- sizeof(struct can_bittiming_const));
- ret = 0;
- } else
- fprintf(stderr, "no bittiming_const data
found\n");
-
- break;
- case GET_BERR_COUNTER:
- if (can_attr[IFLA_CAN_BERR_COUNTER]) {
- memcpy(res,
-
RTA_DATA(can_attr[IFLA_CAN_BERR_COUNTER]),
- sizeof(struct can_berr_counter));
- ret = 0;
- } else
- fprintf(stderr, "no berr_counter data found\n");
-
- break;
+ parse_rtattr_nested(can_attr, IFLA_CAN_MAX,
+ linkinfo[IFLA_INFO_DATA]);
+
+ switch (acquire) {
+ case GET_STATE:
+ if (can_attr[IFLA_CAN_STATE]) {
+ *((int *)res) = *((__u32 *)
+ RTA_DATA(can_attr
+
[IFLA_CAN_STATE]));
+ printf("state: %d\n", *((__u32 *)
+ RTA_DATA(can_attr
+
[IFLA_CAN_STATE])));
+ ret = 0;
+ } else {
+ fprintf(stderr, "no state data
found\n");
+ }
- default:
- fprintf(stderr, "unknown acquire mode\n");
+ break;
+ case GET_RESTART_MS:
+ if (can_attr[IFLA_CAN_RESTART_MS]) {
+ *((__u32 *) res) = *((__u32 *)
+ RTA_DATA(can_attr
+
[IFLA_CAN_RESTART_MS]));
+ ret = 0;
+ } else
+ fprintf(stderr, "no restart_ms data
found\n");
+
+ break;
+ case GET_BITTIMING:
+ if (can_attr[IFLA_CAN_BITTIMING]) {
+ memcpy(res,
+
RTA_DATA(can_attr[IFLA_CAN_BITTIMING]),
+ sizeof(struct can_bittiming));
+ ret = 0;
+ } else
+ fprintf(stderr, "no bittiming data
found\n");
+
+ break;
+ case GET_CTRLMODE:
+ if (can_attr[IFLA_CAN_CTRLMODE]) {
+ memcpy(res,
+
RTA_DATA(can_attr[IFLA_CAN_CTRLMODE]),
+ sizeof(struct can_ctrlmode));
+ ret = 0;
+ } else
+ fprintf(stderr, "no ctrlmode data
found\n");
+
+ break;
+ case GET_CLOCK:
+ if (can_attr[IFLA_CAN_CLOCK]) {
+ memcpy(res,
+
RTA_DATA(can_attr[IFLA_CAN_CLOCK]),
+ sizeof(struct can_clock));
+ ret = 0;
+ } else
+ fprintf(stderr,
+ "no clock parameter data
found\n");
+
+ break;
+ case GET_BITTIMING_CONST:
+ if (can_attr[IFLA_CAN_BITTIMING_CONST]) {
+ memcpy(res,
+
RTA_DATA(can_attr[IFLA_CAN_BITTIMING_CONST]),
+ sizeof(struct
can_bittiming_const));
+ ret = 0;
+ } else
+ fprintf(stderr, "no bittiming_const
data found\n");
+
+ break;
+ case GET_BERR_COUNTER:
+ if (can_attr[IFLA_CAN_BERR_COUNTER]) {
+ memcpy(res,
+
RTA_DATA(can_attr[IFLA_CAN_BERR_COUNTER]),
+ sizeof(struct can_berr_counter));
+ ret = 0;
+ } else
+ fprintf(stderr, "no berr_counter data
found\n");
+
+ break;
+
+ default:
+ fprintf(stderr, "unknown acquire mode\n");
+ }
}
}
+ if ((msglen <= 0) && (errno != EAGAIN)) {
+ perror("Receive error");
+ }
+
return ret;
}
--
1.7.3.4
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