github.com/afumu/libc@v0.0.6/musl/src/network/netlink.c (about)

     1  #include <errno.h>
     2  #include <string.h>
     3  #include <syscall.h>
     4  #include <sys/socket.h>
     5  #include "netlink.h"
     6  
     7  static 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  
    42  int __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  }