Add a "fork" of musl as //fusl.

fusl/src/network/netlink.c

+#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;
+}