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authorLaura Garcia Liebana <nevola@gmail.com>2018-05-17 15:10:34 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2018-05-18 12:47:52 +0200
commite73a16d1e8e98773a8e1cd838bb55720ec088576 (patch)
treec829c5ba3eca80637211541078259483466eaca8 /examples/rtnl/rtnl-neigh-dump.c
parent37c876b55a2c00424ccda5a300ab5fdec1d88b22 (diff)
examples: add arp cache dump example
Adding ARP example in order to dump the info in the form: index=<interface> family=<family> dst=<destination ip> lladdr=<mac address> state=<arp status> Signed-off-by: Laura Garcia Liebana <nevola@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'examples/rtnl/rtnl-neigh-dump.c')
-rw-r--r--examples/rtnl/rtnl-neigh-dump.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/examples/rtnl/rtnl-neigh-dump.c b/examples/rtnl/rtnl-neigh-dump.c
new file mode 100644
index 0000000..fc0f205
--- /dev/null
+++ b/examples/rtnl/rtnl-neigh-dump.c
@@ -0,0 +1,161 @@
+/* This example is placed in the public domain. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/if.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
+static int data_attr_cb(const struct nlattr *attr, void *data)
+{
+ const struct nlattr **tb = data;
+ int type = mnl_attr_get_type(attr);
+
+ /* skip unsupported attribute in user-space */
+ if (mnl_attr_type_valid(attr, IFA_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NDA_DST:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case NDA_LLADDR:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int data_cb(const struct nlmsghdr *nlh, void *data)
+{
+ struct nlattr *tb[IFA_MAX + 1] = {};
+ struct ndmsg *ndm = mnl_nlmsg_get_payload(nlh);
+
+ printf("index=%d family=%d ", ndm->ndm_ifindex, ndm->ndm_family);
+
+ mnl_attr_parse(nlh, sizeof(*ndm), data_attr_cb, tb);
+ printf("dst=");
+ if (tb[NDA_DST]) {
+ void *addr = mnl_attr_get_payload(tb[NDA_DST]);
+ char out[INET6_ADDRSTRLEN];
+
+ if (inet_ntop(ndm->ndm_family, addr, out, sizeof(out)))
+ printf("%s ", out);
+ }
+
+ mnl_attr_parse(nlh, sizeof(*ndm), data_attr_cb, tb);
+ printf("lladdr=");
+ if (tb[NDA_LLADDR]) {
+ void *addr = mnl_attr_get_payload(tb[NDA_LLADDR]);
+ unsigned char lladdr[6] = {0};
+
+ if (memcpy(&lladdr, addr, 6))
+ printf("%02x:%02x:%02x:%02x:%02x:%02x ", lladdr[0], lladdr[1], lladdr[2], lladdr[3], lladdr[4], lladdr[5]);
+ }
+
+ printf("state=");
+ switch(ndm->ndm_state) {
+ case NUD_INCOMPLETE:
+ printf("incomplete ");
+ break;
+ case NUD_REACHABLE:
+ printf("reachable ");
+ break;
+ case NUD_STALE:
+ printf("stale ");
+ break;
+ case NUD_DELAY:
+ printf("delay ");
+ break;
+ case NUD_PROBE:
+ printf("probe ");
+ break;
+ case NUD_FAILED:
+ printf("failed ");
+ break;
+ case NUD_NOARP:
+ printf("noarp ");
+ break;
+ case NUD_PERMANENT:
+ printf("permanent ");
+ break;
+ default:
+ printf("%d ", ndm->ndm_state);
+ break;
+ }
+
+ printf("\n");
+ return MNL_CB_OK;
+}
+
+int main(int argc, char *argv[])
+{
+ struct mnl_socket *nl;
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct nlmsghdr *nlh;
+ struct rtgenmsg *rt;
+ int ret;
+ unsigned int seq, portid;
+
+ if (argc != 2) {
+ fprintf(stderr, "Usage: %s <inet|inet6>\n", argv[0]);
+ exit(EXIT_FAILURE);
+ }
+
+ nlh = mnl_nlmsg_put_header(buf);
+ nlh->nlmsg_type = RTM_GETNEIGH;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ nlh->nlmsg_seq = seq = time(NULL);
+
+ rt = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtgenmsg));
+ if (strcmp(argv[1], "inet") == 0)
+ rt->rtgen_family = AF_INET;
+ else if (strcmp(argv[1], "inet6") == 0)
+ rt->rtgen_family = AF_INET6;
+
+ nl = mnl_socket_open(NETLINK_ROUTE);
+ if (nl == NULL) {
+ perror("mnl_socket_open");
+ exit(EXIT_FAILURE);
+ }
+
+ if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+ perror("mnl_socket_bind");
+ exit(EXIT_FAILURE);
+ }
+ portid = mnl_socket_get_portid(nl);
+
+ if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+ perror("mnl_socket_sendto");
+ exit(EXIT_FAILURE);
+ }
+
+ ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+ while (ret > 0) {
+ ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
+ if (ret <= MNL_CB_STOP)
+ break;
+ ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+ }
+
+ if (ret == -1) {
+ perror("error");
+ exit(EXIT_FAILURE);
+ }
+
+ mnl_socket_close(nl);
+
+ return 0;
+}