/* Tries to receive an openflow message from datapath 'dp_idx' on 'sock'. If
* successful, stores the received message into '*msgp' and returns 0. The
* caller is responsible for destroying the message with ofpbuf_delete(). On
* failure, returns a positive errno value and stores a null pointer into
* '*msgp'.
*
* Only Netlink messages with embedded OpenFlow messages are accepted. Other
* Netlink messages provoke errors.
*
* If 'wait' is true, dpif_recv_openflow waits for a message to be ready;
* otherwise, returns EAGAIN if the 'sock' receive buffer is empty. */
int
dpif_recv_openflow(struct dpif *dp, int dp_idx, struct ofpbuf **bufferp,
bool wait)
{
struct nlattr *attrs[ARRAY_SIZE(openflow_policy)];
struct ofpbuf *buffer;
struct ofp_header *oh;
uint16_t ofp_len;
buffer = *bufferp = NULL;
do {
int retval;
do {
ofpbuf_delete(buffer);
retval = nl_sock_recv(dp->sock, &buffer, wait);
} while (retval == ENOBUFS
|| (!retval
&& (nl_msg_nlmsghdr(buffer)->nlmsg_type == NLMSG_DONE
|| nl_msg_nlmsgerr(buffer, NULL))));
if (retval) {
if (retval != EAGAIN) {
VLOG_WARN_RL(&rl, "dpif_recv_openflow: %s", strerror(retval));
}
return retval;
}
if (nl_msg_genlmsghdr(buffer) == NULL) {
VLOG_DBG_RL(&rl, "received packet too short for Generic Netlink");
goto error;
}
if (nl_msg_nlmsghdr(buffer)->nlmsg_type != openflow_family) {
VLOG_DBG_RL(&rl,
"received type (%"PRIu16") != openflow family (%d)",
nl_msg_nlmsghdr(buffer)->nlmsg_type, openflow_family);
goto error;
}
if (!nl_policy_parse(buffer, NLMSG_HDRLEN + GENL_HDRLEN,
openflow_policy, attrs,
ARRAY_SIZE(openflow_policy))) {
goto error;
}
} while (nl_attr_get_u32(attrs[DP_GENL_A_DP_IDX]) != dp_idx);
oh = buffer->data = (void *) nl_attr_get(attrs[DP_GENL_A_OPENFLOW]);
buffer->size = nl_attr_get_size(attrs[DP_GENL_A_OPENFLOW]);
ofp_len = ntohs(oh->length);
if (ofp_len != buffer->size) {
VLOG_WARN_RL(&rl,
"ofp_header.length %"PRIu16" != attribute length %zu\n",
ofp_len, buffer->size);
buffer->size = MIN(ofp_len, buffer->size);
}
*bufferp = buffer;
return 0;
error:
ofpbuf_delete(buffer);
return EPROTO;
}
int
main(int argc OVS_UNUSED, char *argv[])
{
uint64_t buf_stub[4096 / 64];
struct nl_sock *sock;
struct ofpbuf buf;
int error;
set_program_name(argv[0]);
vlog_set_levels(NULL, VLF_ANY_FACILITY, VLL_DBG);
error = nl_sock_create(NETLINK_ROUTE, &sock);
if (error) {
ovs_fatal(error, "could not create rtnetlink socket");
}
error = nl_sock_join_mcgroup(sock, RTNLGRP_LINK);
if (error) {
ovs_fatal(error, "could not join RTNLGRP_LINK multicast group");
}
ofpbuf_use_stub(&buf, buf_stub, sizeof buf_stub);
for (;;) {
error = nl_sock_recv(sock, &buf, false);
if (error == EAGAIN) {
/* Nothing to do. */
} else if (error == ENOBUFS) {
ovs_error(0, "network monitor socket overflowed");
} else if (error) {
ovs_fatal(error, "error on network monitor socket");
} else {
struct iff_flag {
unsigned int flag;
const char *name;
};
static const struct iff_flag flags[] = {
{ IFF_UP, "UP", },
{ IFF_BROADCAST, "BROADCAST", },
#ifndef _WIN32
{ IFF_DEBUG, "DEBUG", },
#endif
{ IFF_LOOPBACK, "LOOPBACK", },
#ifndef _WIN32
{ IFF_POINTOPOINT, "POINTOPOINT", },
{ IFF_NOTRAILERS, "NOTRAILERS", },
#endif
{ IFF_RUNNING, "RUNNING", },
#ifndef _WIN32
{ IFF_NOARP, "NOARP", },
#endif
{ IFF_PROMISC, "PROMISC", },
#ifndef _WIN32
{ IFF_ALLMULTI, "ALLMULTI", },
{ IFF_MASTER, "MASTER", },
{ IFF_SLAVE, "SLAVE", },
#endif
{ IFF_MULTICAST, "MULTICAST", },
#ifndef _WIN32
{ IFF_PORTSEL, "PORTSEL", },
{ IFF_AUTOMEDIA, "AUTOMEDIA", },
{ IFF_DYNAMIC, "DYNAMIC", },
#endif
};
struct nlattr *attrs[ARRAY_SIZE(rtnlgrp_link_policy)];
struct nlmsghdr *nlh;
struct ifinfomsg *iim;
int i;
nlh = ofpbuf_at(&buf, 0, NLMSG_HDRLEN);
iim = ofpbuf_at(&buf, NLMSG_HDRLEN, sizeof *iim);
if (!iim) {
ovs_error(0, "received bad rtnl message (no ifinfomsg)");
continue;
}
if (!nl_policy_parse(&buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
rtnlgrp_link_policy,
attrs, ARRAY_SIZE(rtnlgrp_link_policy))) {
ovs_error(0, "received bad rtnl message (policy)");
continue;
}
printf("netdev %s changed (%s):\n",
nl_attr_get_string(attrs[IFLA_IFNAME]),
(nlh->nlmsg_type == RTM_NEWLINK ? "RTM_NEWLINK"
#ifndef _WIN32
: nlh->nlmsg_type == RTM_DELLINK ? "RTM_DELLINK"
#endif
: nlh->nlmsg_type == RTM_GETLINK ? "RTM_GETLINK"
#ifndef _WIN32
: nlh->nlmsg_type == RTM_SETLINK ? "RTM_SETLINK"
#endif
: "other"));
printf("\tflags:");
for (i = 0; i < ARRAY_SIZE(flags); i++) {
if (iim->ifi_flags & flags[i].flag) {
printf(" %s", flags[i].name);
}
}
printf("\n");
if (attrs[IFLA_MASTER]) {
uint32_t idx = nl_attr_get_u32(attrs[IFLA_MASTER]);
char ifname[IFNAMSIZ];
#ifndef _WIN32
if (!if_indextoname(idx, ifname)) {
strcpy(ifname, "unknown");
}
#endif
printf("\tmaster=%"PRIu32" (%s)\n", idx, ifname);
}
}
nl_sock_wait(sock, POLLIN);
poll_block();
}
}
