Liunx下用代码设置ip地址

之前写过一个ifconfig版本的IP地址设置，但是不能设置保留的E类地址。最近看了下iproute的源码，移植了一下，现在E类IP地址也可以配了。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>
#include <limits.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/if_link.h>
#include <linux/if_addr.h>
#include <linux/neighbour.h>
#include <linux/netconf.h>

#define MAX_BUF_SIZE    32768
#define INFINITY_LIFE_TIME  0xFFFFFFFFU
#define NLMSG_TAIL(nmsg) \
	((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))

typedef struct 
{
	__u16 flags;
	__u16 bytelen;
	__s16 bitlen;
	__u16 family;
	__u32 data[8];
} inet_prefix;

struct rtnl_handle
{
	int fd;
	struct sockaddr_nl local;
	struct sockaddr_nl peer;
	__u32 seq;
	__u32 dump;
	int proto;
	FILE *dump_fp;
#define RTNL_HANDLE_F_LISTEM_ALL_NSID        0x01
	int flags;
};

struct rtnl_handle rth = { .fd = -1 };

void rtnl_close(struct rtnl_handle *rth)
{
	if (rth->fd >= 0)
	{
		close(rth->fd);
		rth->fd = -1;
	}
}

int rtnl_open_byproto(struct rtnl_handle *rth, unsigned subscriptions,
		int protocol)
{
	socklen_t addr_len;
	int sndbuf = 32768;
	int rcvbuf = 1024 * 1024;

	memset(rth, 0, sizeof(*rth));

	rth->proto = protocol;
	rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
	if (rth->fd < 0)
	{
		perror("Cannot open netlink socket!");
		return -1;
	}

	if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) 
			< 0)
	{
		perror("SO_SNDBUF");
		return -1;
	}

	if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) 
			< 0)
	{
		perror("SO_RECVBUF");
		return -1;
	}

    memset(&rth->local, 0, sizeof(rth->local));
	rth->local.nl_family = AF_NETLINK;
	rth->local.nl_groups = subscriptions;

	if (bind(rth->fd, (struct sockaddr *)&rth->local, sizeof(rth->local)) < 0)
	{
		perror("Cannot bind netlin socket");
		return -1;
	}

	addr_len = sizeof(rth->local);
	if (getsockname(rth->fd, (struct sockaddr *)&rth->local, &addr_len) < 0)
	{
		perror("Cannot getsockname");
		return -1;
	}

	if (rth->local.nl_family != AF_NETLINK)
	{
		fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family);
		return -1;
	}

	rth->seq = time(NULL);
	return 0;
}

int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
{
	return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
}

int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
		struct nlmsghdr *answer, size_t maxlen)
{
	int status;
	unsigned seq;
	struct nlmsghdr *h;
	struct sockaddr_nl nladdr;
	struct iovec iov = {
		.iov_base = (void *) n,
		.iov_len = n->nlmsg_len
	};
    struct msghdr msg = {
		.msg_name = &nladdr,
		.msg_namelen = sizeof(nladdr),
		.msg_iov = &iov,
		.msg_iovlen = 1
	};
	char buf[MAX_BUF_SIZE];

	memset(&nladdr, 0, sizeof(nladdr));
	nladdr.nl_family = AF_NETLINK;

	n->nlmsg_seq = seq = ++rtnl->seq;

	if (answer == NULL)
	{
		n->nlmsg_flags |= NLM_F_ACK;
	}

	status = sendmsg(rtnl->fd, &msg, 0);
	if (status < 0)
	{
		fprintf(stderr, "sendmsg error: %d - %s \n", errno, strerror(errno));
		return -1;
	}

	memset(buf, 0, sizeof(buf));
	iov.iov_base = buf;
	while (1)
	{
		iov.iov_len = sizeof(buf);
		status = recvmsg(rtnl->fd, &msg, 0);

		if (status < 0)
		{
			if (errno == EINTR || errno == EAGAIN)
			{
				continue;
			}

			return -1;
		}

		if (status == 0)
		{
			return -1;
		}

		if (msg.msg_namelen != sizeof(nladdr))
		{
			return -1;
		}

        for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); )
		{
			int len = h->nlmsg_len;
			int l = len - sizeof(*h);

			if (l < 0 || len > status)
			{
				return -1;
			}

			if (nladdr.nl_pid != 0 ||
					h->nlmsg_pid != rtnl->local.nl_pid ||
					h->nlmsg_seq != seq)
			{
				status -= NLMSG_ALIGN(len);
				h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
				continue;
			}

			if (h->nlmsg_type == NLMSG_ERROR)
			{
				struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
				if (l < sizeof(struct nlmsgerr))
				{

				}
				else if (!err->error)
				{
					if (answer)
					{
						memcpy(answer, h, ((maxlen) < (h->nlmsg_len) ? 
									(maxlen) : (h->nlmsg_len))); 
					}
	
					return 0;
				}

				fprintf(stderr, "RTNETLINK answers: %s\n",
						strerror(-err->error));
				return -1;
			}

			if (answer)
			{
				memcpy(answer, h, ((maxlen) < (h->nlmsg_len) ? (maxlen) :
							h->nlmsg_len));
				return 0;
			}

			status -= NLMSG_ALIGN(len);
			h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
		}

		if (msg.msg_flags & MSG_TRUNC)
		{
			continue;
		}

		if (status)
		{
			fprintf(stderr, "!!!Remnat of size %d\n", status);
			return -1;
		}
	}
}

int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data, 
		int alen)
{
	int len = RTA_LENGTH(alen);
	struct rtattr *rta;

	if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen)
	{
		return -1;
	}

	rta = NLMSG_TAIL(n);
	rta->rta_type = type;
    rta->rta_len = len;
	memcpy(RTA_DATA(rta), data, alen);
	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);

	return 0;
}

int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
{
	return addattr_l(n, maxlen, type, &data, sizeof(__u32));
}

unsigned ll_name_to_index(const char *name)
{
	unsigned index;
	index = if_nametoindex(name);
	printf("the index of %s is %d\n", name, index);
	if (index == 0)
	{
		sscanf(name, "if%u", &index);
	}

	return index;
}

int get_addr_ipv4(__u8 *ap, const char *cp)
{
	int i;

	printf("Debug - ipv4: %s\n", cp);

	for (i = 0; i < 4; i++)
	{
		unsigned long n;
		char *endp;

		n = strtoul(cp, &endp, 0);
		if (n > 255)
		{
			return -1;
		}

		if (endp == cp)
		{
			return -1;
		}

		ap[i] = n;

		if (*endp == '\0')
			break;

		if (i == 3 || *endp != '.')
		{
			return -1;
		}

		cp = endp + 1;
	}

	return 1;
}

int get_addr_1(inet_prefix *addr, const char *name, int family)
{
	memset(addr, 0, sizeof(*addr));

	if (strcmp(name, "default") == 0 ||
	    strcmp(name, "all") == 0 ||
	    strcmp(name, "any") == 0) 
	{
		addr->family = family;
		addr->bytelen = (family == AF_INET6 ? 16 : 4);
		addr->bitlen = -1;
		return 0;
	}

	if (strchr(name, ':')) 
	{
		addr->family = AF_INET6;
		if (family != AF_UNSPEC && family != AF_INET6)
			return -1;
		if (inet_pton(AF_INET6, name, addr->data) <= 0)
			return -1;
		addr->bytelen = 16;
		addr->bitlen = -1;
		return 0;
	}

	addr->family = AF_INET;
	if (family != AF_UNSPEC && family != AF_INET)
		return -1;

	if (get_addr_ipv4((__u8 *)addr->data, name) <= 0)
		return -1;

	addr->bytelen = 4;
	addr->bitlen = -1;
	return 0;
}

int get_unsigned(unsigned *val, const char *arg, int base)
{
	unsigned long res;
	char *ptr;

	if (!arg || !*arg)
		return -1;

	res = strtoul(arg, &ptr, base);

	/* empty string or trailing non-digits */
	if (!ptr || ptr == arg || *ptr)
		return -1;

	/* overflow */
	if (res == ULONG_MAX && errno == ERANGE)
		return -1;

	/* out side range of unsigned */
	if (res > UINT_MAX)
		return -1;

	*val = res;
	return 0;
}

int mask2bits(__u32 netmask)
{
	unsigned bits = 0;
	__u32 mask = ntohl(netmask);
	__u32 host = ~mask;

	if ((host & (host + 1)) != 0)
	{
		return -1;
	}

	for (; mask; mask <<= 1)
	{
		++bits;
	}

	return bits;
}

int get_netmask(unsigned *val, const char *arg, int base)
{
	inet_prefix addr;

	if (!get_unsigned(val, arg, base))
		return 0;

	/* try coverting dotted quad to CIDR */
	if (!get_addr_1(&addr, arg, AF_INET) && addr.family == AF_INET) {
		int b = mask2bits(addr.data[0]);
		
		if (b >= 0) {
			*val = b;
			return 0;
		}
	}

	return -1;
}

int af_bit_len(int af)
{
	switch (af)
	{
		case AF_INET6:
			return 128;
		case AF_INET:
			return 32;
		case AF_DECnet:
			return 16;
		case AF_IPX:
			return 80;
	}

	return 0;
}

int get_prefix_1(inet_prefix *dst, char *arg, int family)
{
	int err;
	unsigned plen;
	char *slash;

	memset(dst, 0, sizeof(*dst));

	if (strcmp(arg, "default") == 0 ||
	    strcmp(arg, "any") == 0 ||
	    strcmp(arg, "all") == 0) 
	{
		dst->family = family;
		dst->bytelen = 0;
		dst->bitlen = 0;
		return 0;
	}

	slash = strchr(arg, '/');
	if (slash)
		*slash = 0;

	err = get_addr_1(dst, arg, family);
	if (err == 0) 
	{
		dst->bitlen = af_bit_len(dst->family);

		if (slash) 
		{
			if (get_netmask(&plen, slash+1, 0)
			    || plen > dst->bitlen) 
			{
				err = -1;
				goto done;
			}
			dst->flags |= 0x1;
			dst->bitlen = plen;
		}
	}
done:
	if (slash)
		*slash = '/';
	return err;	
}

int get_prefix(inet_prefix *dst, char *arg, int family)
{
	if (family == AF_PACKET) 
	{
        return -1;
	}

	if (get_prefix_1(dst, arg, family)) 
	{
        return -1;
	}
	return 0;
}

int default_scope(inet_prefix *lcl)
{
	if (lcl->family == AF_INET)
	{
		if (lcl->bytelen >= 1 && *(__u8 *)&lcl->data == 127)
		{
			return RT_SCOPE_HOST;
		}
	}

	return 0;
}

int matches(const char *cmd, const char *pattern)
{
	int len = strlen(cmd);
	if (len > strlen(pattern))
	{
		return -1;
	}

	return memcmp(pattern, cmd, len);
}

int ipaddr_modify(int cmd, int flags, int argc, char **argv)
{
	struct
	{
		struct nlmsghdr n;
		struct ifaddrmsg ifa;
		char buf[256];
	} req;
	
	char *d = NULL;
	char *l = NULL;
	char *lcl_arg = NULL;
	char *valid_lftp = NULL;
	char *perferred_lftp = NULL;
	inet_prefix lcl;
	inet_prefix peer;
	int local_len = 0;
	int perr_len = 0;
	int any_len = 0;
	int scoped = 0;
	int ret = 0;
	__u32 preferred_lft = INFINITY_LIFE_TIME;
	__u32 valid_left = INFINITY_LIFE_TIME;
	struct ifa_cacheinfo cinfo;
	unsigned int ifa_flags = 0;

	memset(&req, 0, sizeof(req));

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
	req.n.nlmsg_flags = NLM_F_REQUEST | flags;
	req.n.nlmsg_type = cmd;
	req.ifa.ifa_family = AF_INET;

	while (argc > 0)
	{
		if (strcmp(*argv, "dev") == 0)
		{
			argv++;
			if (--argc <= 0)
			{
				ret = -1;
				break;
			}

			d = *argv;
		}
		else
		{
			lcl_arg = *argv;
			get_prefix(&lcl, *argv, req.ifa.ifa_family);
			if (req.ifa.ifa_family == AF_UNSPEC)
			{
				req.ifa.ifa_family = lcl.family;
			}

			addattr_l(&req.n, sizeof(req), IFA_LOCAL, &lcl.data, lcl.bytelen);
			local_len = lcl.bytelen;
		}

		argc--;
		argv++;
	}

	if (ifa_flags <= 0xff)
	{
		req.ifa.ifa_flags = ifa_flags;
	}
	else
	{
		//addattr32(&req.n, sizeof(req), IFA_FLAGS, ifa_flags);
	}

	if (d == NULL)
	{
		return -1;
	}

    if (local_len)
	{
		if (cmd == RTM_DELADDR && lcl.family == AF_INET 
				&& !(lcl.flags & 0x01))
		{
	        
		}
		else
		{
			addattr_l(&req.n, sizeof(req), IFA_ADDRESS, &lcl.data, lcl.bytelen);
		}
	}

	if (req.ifa.ifa_prefixlen == 0)
	{
		req.ifa.ifa_prefixlen = lcl.bitlen;
	}

	if (!scoped && cmd != RTM_DELADDR)
	{
		req.ifa.ifa_scope = default_scope(&lcl);
	}

    if ((req.ifa.ifa_index = ll_name_to_index(d)) == 0)
	{
		return -1;
	}

    if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)
	{
		return -2;
	}

	return 0;
}

int do_ipaddr(int argc, char **argv)
{
    if (matches(*argv, "add") == 0)
	{
		return ipaddr_modify(RTM_NEWADDR, NLM_F_CREATE | NLM_F_EXCL, argc - 1,
				argv + 1);
	}
	
	if (matches(*argv, "delete") == 0)
	{
		return ipaddr_modify(RTM_DELADDR, 0, argc - 1, argv + 1);
	}

	if (matches(*argv, "change") == 0 || strcmp(*argv, "chg") == 0)
	{
		return ipaddr_modify(RTM_NEWADDR, NLM_F_REPLACE, argc - 1, argv + 1);
	}

	return -1;
}
 

int main(int argc, char **argv)
{
	if (argc != 4)
	{
		printf("usage: %s add/del <ip> dev <interface>\n", argv[0]);
		printf("eg   : %s add 192.168.1.2/24 dev eth0\n", argv[0]);
		printf("       %s del 192.168.1.2/24 dev eth0\n", argv[0]);
		return 1;
	}
	
    if (rtnl_open(&rth, 0) < 0)
	{
		rtnl_close(&rth);
		return 1;
	}

	int ret = do_ipaddr(argc - 1, ++argv);
	printf("ret = %d\n", ret);

	rtnl_close(&rth);

	return 0;
}