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samples: bpf: Convert route table network order fields into readable format

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The route table that is dumped when the xdp_router_ipv4 process is launched
has the "Gateway" field in non-readable network byte order format, also the
alignment is off when printing the table.

Destination             Gateway         Genmask         Metric          Iface
  0.0.0.0               196a8c0         0               0               enp7s0
  0.0.0.0               196a8c0         0               0               wlp6s0
169.254.0.0             196a8c0         16              0               enp7s0
172.17.0.0                0             16              0               docker0
192.168.150.0             0             24              0               enp7s0
192.168.150.0             0             24              0               wlp6s0

Fix this by converting the "Gateway" field from network byte order Hex into
dotted decimal notation IPv4 format and "Genmask" from CIDR notation into
dotted decimal notation IPv4 format. Also fix the aligntment of the fields
in the route table.

Destination     Gateway         Genmask         Metric Iface
0.0.0.0         192.168.150.1   0.0.0.0         0      enp7s0
0.0.0.0         192.168.150.1   0.0.0.0         0      wlp6s0
169.254.0.0     192.168.150.1   255.255.0.0     0      enp7s0
172.17.0.0      0.0.0.0         255.255.0.0     0      docker0
192.168.150.0   0.0.0.0         255.255.255.0   0      enp7s0
192.168.150.0   0.0.0.0         255.255.255.0   0      wlp6s0

Signed-off-by: Gokul Sivakumar <gokulkumar792@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210919080305.173588-1-gokulkumar792@gmail.com
This commit is contained in:
Gokul Sivakumar 2021-09-19 13:33:04 +05:30 committed by Alexei Starovoitov
parent 97c140d94e
commit f5c4e4191b
1 changed files with 13 additions and 9 deletions
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22
samples/bpf/xdp_router_ipv4_user.c
View File

@ -155,7 +155,7 @@ static void read_route(struct nlmsghdr *nh, int nll)
printf("%d\n", nh->nlmsg_type);
memset(&route, 0, sizeof(route));
printf("Destination\t\tGateway\t\tGenmask\t\tMetric\t\tIface\n");
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;
@ -207,6 +207,7 @@ static void read_route(struct nlmsghdr *nh, int nll)
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));
@ -234,14 +235,17 @@ static void read_route(struct nlmsghdr *nh, int nll)
for (i = 0; i < 4; i++)
prefix_key->data[i] = (route.dst >> i * 8) & 0xff;
printf("%3d.%d.%d.%d\t\t%3x\t\t%d\t\t%d\t\t%s\n",
(int)prefix_key->data[0],
(int)prefix_key->data[1],
(int)prefix_key->data[2],
(int)prefix_key->data[3],
route.gw, route.dst_len,
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++)
@ -672,7 +676,7 @@ int main(int ac, char **argv)
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
printf("\n**************loading bpf file*********************\n\n\n");
printf("\n******************loading bpf file*********************\n");
if (!prog_fd) {
printf("bpf_prog_load_xattr: %s\n", strerror(errno));
return 1;
@ -722,7 +726,7 @@ int main(int ac, char **argv)
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
printf("*******************ROUTE TABLE*************************\n\n\n");
printf("\n*******************ROUTE TABLE*************************\n");
get_route_table(AF_INET);
printf("*******************ARP TABLE***************************\n\n\n");
get_arp_table(AF_INET);