source: asp3_tinet_ecnl_rx/trunk/musl-1.1.18/src/network/netlink.c@ 337

#include <errno.h>
#include <string.h>
#include <syscall.h>
#include <sys/socket.h>
#include "netlink.h"

static int __netlink_enumerate(int fd, unsigned int seq, int type, int af,
        int (*cb)(void *ctx, struct nlmsghdr *h), void *ctx)
{
        struct nlmsghdr *h;
        union {
                uint8_t buf[8192];
                struct {
                        struct nlmsghdr nlh;
                        struct rtgenmsg g;
                } req;
                struct nlmsghdr reply;
        } u;
        int r, ret;

        memset(&u.req, 0, sizeof(u.req));
        u.req.nlh.nlmsg_len = sizeof(u.req);
        u.req.nlh.nlmsg_type = type;
        u.req.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
        u.req.nlh.nlmsg_seq = seq;
        u.req.g.rtgen_family = af;
        r = send(fd, &u.req, sizeof(u.req), 0);
        if (r < 0) return r;

        while (1) {
                r = recv(fd, u.buf, sizeof(u.buf), MSG_DONTWAIT);
                if (r <= 0) return -1;
                for (h = &u.reply; NLMSG_OK(h, (void*)&u.buf[r]); h = NLMSG_NEXT(h)) {
                        if (h->nlmsg_type == NLMSG_DONE) return 0;
                        if (h->nlmsg_type == NLMSG_ERROR) return -1;
                        ret = cb(ctx, h);
                        if (ret) return ret;
                }
        }
}

int __rtnetlink_enumerate(int link_af, int addr_af, int (*cb)(void *ctx, struct nlmsghdr *h), void *ctx)
{
        int fd, r;

        fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE);
        if (fd < 0) return -1;
        r = __netlink_enumerate(fd, 1, RTM_GETLINK, link_af, cb, ctx);
        if (!r) r = __netlink_enumerate(fd, 2, RTM_GETADDR, addr_af, cb, ctx);
        __syscall(SYS_close,fd);
        return r;
}