in bpf/xdp_router_ipv4_user.c [122:313]
static void read_route(struct nlmsghdr *nh, int nll)
{
char dsts[24], gws[24], ifs[16], dsts_len[24], metrics[24];
struct bpf_lpm_trie_key *prefix_key;
struct rtattr *rt_attr;
struct rtmsg *rt_msg;
int rtm_family;
int rtl;
int i;
struct route_table {
int dst_len, iface, metric;
char *iface_name;
__be32 dst, gw;
__be64 mac;
} route;
struct arp_table {
__be64 mac;
__be32 dst;
};
struct direct_map {
struct arp_table arp;
int ifindex;
__be64 mac;
} direct_entry;
if (nh->nlmsg_type == RTM_DELROUTE)
printf("DELETING Route entry\n");
else if (nh->nlmsg_type == RTM_GETROUTE)
printf("READING Route entry\n");
else if (nh->nlmsg_type == RTM_NEWROUTE)
printf("NEW Route entry\n");
else
printf("%d\n", nh->nlmsg_type);
memset(&route, 0, sizeof(route));
printf("Destination Gateway Genmask Metric Iface\n");
for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
rt_msg = (struct rtmsg *)NLMSG_DATA(nh);
rtm_family = rt_msg->rtm_family;
if (rtm_family == AF_INET)
if (rt_msg->rtm_table != RT_TABLE_MAIN)
continue;
rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
rtl = RTM_PAYLOAD(nh);
for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
switch (rt_attr->rta_type) {
case NDA_DST:
sprintf(dsts, "%u",
(*((__be32 *)RTA_DATA(rt_attr))));
break;
case RTA_GATEWAY:
sprintf(gws, "%u",
*((__be32 *)RTA_DATA(rt_attr)));
break;
case RTA_OIF:
sprintf(ifs, "%u",
*((int *)RTA_DATA(rt_attr)));
break;
case RTA_METRICS:
sprintf(metrics, "%u",
*((int *)RTA_DATA(rt_attr)));
default:
break;
}
}
sprintf(dsts_len, "%d", rt_msg->rtm_dst_len);
route.dst = atoi(dsts);
route.dst_len = atoi(dsts_len);
route.gw = atoi(gws);
route.iface = atoi(ifs);
route.metric = atoi(metrics);
route.iface_name = alloca(sizeof(char *) * IFNAMSIZ);
route.iface_name = if_indextoname(route.iface, route.iface_name);
route.mac = getmac(route.iface_name);
if (route.mac == -1)
int_exit(0);
assert(bpf_map_update_elem(tx_port_map_fd,
&route.iface, &route.iface, 0) == 0);
if (rtm_family == AF_INET) {
struct trie_value {
__u8 prefix[4];
__be64 value;
int ifindex;
int metric;
__be32 gw;
} *prefix_value;
struct in_addr dst_addr, gw_addr, mask_addr;
prefix_key = alloca(sizeof(*prefix_key) + 3);
prefix_value = alloca(sizeof(*prefix_value));
prefix_key->prefixlen = 32;
prefix_key->prefixlen = route.dst_len;
direct_entry.mac = route.mac & 0xffffffffffff;
direct_entry.ifindex = route.iface;
direct_entry.arp.mac = 0;
direct_entry.arp.dst = 0;
if (route.dst_len == 32) {
if (nh->nlmsg_type == RTM_DELROUTE) {
assert(bpf_map_delete_elem(exact_match_map_fd,
&route.dst) == 0);
} else {
if (bpf_map_lookup_elem(arp_table_map_fd,
&route.dst,
&direct_entry.arp.mac) == 0)
direct_entry.arp.dst = route.dst;
assert(bpf_map_update_elem(exact_match_map_fd,
&route.dst,
&direct_entry, 0) == 0);
}
}
for (i = 0; i < 4; i++)
prefix_key->data[i] = (route.dst >> i * 8) & 0xff;
dst_addr.s_addr = route.dst;
printf("%-16s", inet_ntoa(dst_addr));
gw_addr.s_addr = route.gw;
printf("%-16s", inet_ntoa(gw_addr));
mask_addr.s_addr = htonl(~(0xffffffffU >> route.dst_len));
printf("%-16s%-7d%s\n", inet_ntoa(mask_addr),
route.metric,
route.iface_name);
if (bpf_map_lookup_elem(lpm_map_fd, prefix_key,
prefix_value) < 0) {
for (i = 0; i < 4; i++)
prefix_value->prefix[i] = prefix_key->data[i];
prefix_value->value = route.mac & 0xffffffffffff;
prefix_value->ifindex = route.iface;
prefix_value->gw = route.gw;
prefix_value->metric = route.metric;
assert(bpf_map_update_elem(lpm_map_fd,
prefix_key,
prefix_value, 0
) == 0);
} else {
if (nh->nlmsg_type == RTM_DELROUTE) {
printf("deleting entry\n");
printf("prefix key=%d.%d.%d.%d/%d",
prefix_key->data[0],
prefix_key->data[1],
prefix_key->data[2],
prefix_key->data[3],
prefix_key->prefixlen);
assert(bpf_map_delete_elem(lpm_map_fd,
prefix_key
) == 0);
/* Rereading the route table to check if
* there is an entry with the same
* prefix but a different metric as the
* deleted enty.
*/
get_route_table(AF_INET);
} else if (prefix_key->data[0] ==
prefix_value->prefix[0] &&
prefix_key->data[1] ==
prefix_value->prefix[1] &&
prefix_key->data[2] ==
prefix_value->prefix[2] &&
prefix_key->data[3] ==
prefix_value->prefix[3] &&
route.metric >= prefix_value->metric) {
continue;
} else {
for (i = 0; i < 4; i++)
prefix_value->prefix[i] =
prefix_key->data[i];
prefix_value->value =
route.mac & 0xffffffffffff;
prefix_value->ifindex = route.iface;
prefix_value->gw = route.gw;
prefix_value->metric = route.metric;
assert(bpf_map_update_elem(lpm_map_fd,
prefix_key,
prefix_value,
0) == 0);
}
}
}
memset(&route, 0, sizeof(route));
memset(dsts, 0, sizeof(dsts));
memset(dsts_len, 0, sizeof(dsts_len));
memset(gws, 0, sizeof(gws));
memset(ifs, 0, sizeof(ifs));
memset(&route, 0, sizeof(route));
}
}