1#include <errno.h>
2#include <string.h>
3#include <syscall.h>
4#include <sys/socket.h>
5#include "netlink.h"
6
7static int __netlink_enumerate(int fd, unsigned int seq, int type, int af,
8 int (*cb)(void *ctx, struct nlmsghdr *h), void *ctx)
9{
10 struct nlmsghdr *h;
11 union {
12 uint8_t buf[8192];
13 struct {
14 struct nlmsghdr nlh;
15 struct rtgenmsg g;
16 } req;
17 struct nlmsghdr reply;
18 } u;
19 int r, ret;
20
21 memset(&u.req, 0, sizeof(u.req));
22 u.req.nlh.nlmsg_len = sizeof(u.req);
23 u.req.nlh.nlmsg_type = type;
24 u.req.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
25 u.req.nlh.nlmsg_seq = seq;
26 u.req.g.rtgen_family = af;
27 r = send(fd, &u.req, sizeof(u.req), 0);
28 if (r < 0) return r;
29
30 while (1) {
31 r = recv(fd, u.buf, sizeof(u.buf), MSG_DONTWAIT);
32 if (r <= 0) return -1;
33 for (h = &u.reply; NLMSG_OK(h, (void*)&u.buf[r]); h = NLMSG_NEXT(h)) {
34 if (h->nlmsg_type == NLMSG_DONE) return 0;
35 if (h->nlmsg_type == NLMSG_ERROR) return -1;
36 ret = cb(ctx, h);
37 if (ret) return ret;
38 }
39 }
40}
41
42int __rtnetlink_enumerate(int link_af, int addr_af, int (*cb)(void *ctx, struct nlmsghdr *h), void *ctx)
43{
44 int fd, r;
45
46 fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE);
47 if (fd < 0) return -1;
48 r = __netlink_enumerate(fd, 1, RTM_GETLINK, link_af, cb, ctx);
49 if (!r) r = __netlink_enumerate(fd, 2, RTM_GETADDR, addr_af, cb, ctx);
50 __syscall(SYS_close,fd);
51 return r;
52}