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| | #define _GNU_SOURCE
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <net/if.h>
#include "__netlink.h"
/* getifaddrs() uses PF_PACKET to relay hardware addresses.
* But Infiniband socket address length is longer, so use this hack
* (like glibc) to return it anyway. */
struct sockaddr_ll_hack {
unsigned short sll_family, sll_protocol;
int sll_ifindex;
unsigned short sll_hatype;
unsigned char sll_pkttype, sll_halen;
unsigned char sll_addr[24];
};
union sockany {
struct sockaddr sa;
struct sockaddr_ll_hack ll;
struct sockaddr_in v4;
struct sockaddr_in6 v6;
};
struct ifaddrs_storage {
struct ifaddrs ifa;
struct ifaddrs_storage *hash_next;
union sockany addr, netmask, ifu;
unsigned int index;
char name[IFNAMSIZ+1];
};
#define IFADDRS_HASH_SIZE 64
struct ifaddrs_ctx {
struct ifaddrs_storage *first;
struct ifaddrs_storage *last;
struct ifaddrs_storage *hash[IFADDRS_HASH_SIZE];
};
void freeifaddrs(struct ifaddrs *ifp)
{
struct ifaddrs *n;
while (ifp) {
n = ifp->ifa_next;
free(ifp);
ifp = n;
}
}
static void addifaddrs(struct ifaddrs_ctx *ctx, struct ifaddrs_storage *add)
{
if (!add->ifa.ifa_name) {
free(add);
return;
}
if (!ctx->first) ctx->first = add;
if (ctx->last) ctx->last->ifa.ifa_next = &add->ifa;
ctx->last = add;
}
static struct sockaddr* copy_lladdr(union sockany *sa, struct rtattr *rta, struct ifinfomsg *ifi)
{
if (RTA_DATALEN(rta) > sizeof(sa->ll.sll_addr)) return 0;
sa->ll.sll_family = AF_PACKET;
sa->ll.sll_ifindex = ifi->ifi_index;
sa->ll.sll_hatype = ifi->ifi_type;
sa->ll.sll_halen = RTA_DATALEN(rta);
memcpy(sa->ll.sll_addr, RTA_DATA(rta), RTA_DATALEN(rta));
return &sa->sa;
}
static uint8_t *sockany_addr(int af, union sockany *sa, int *len)
{
switch (af) {
case AF_INET: *len = 4; return (uint8_t*) &sa->v4.sin_addr;
case AF_INET6: *len = 16; return (uint8_t*) &sa->v6.sin6_addr;
}
return 0;
}
static struct sockaddr* copy_addr(int af, union sockany *sa, struct rtattr *rta)
{
int len;
uint8_t *dst = sockany_addr(af, sa, &len);
if (!dst || RTA_DATALEN(rta) != len) return 0;
sa->sa.sa_family = af;
memcpy(dst, RTA_DATA(rta), len);
return &sa->sa;
}
static struct sockaddr *gen_netmask(int af, union sockany *sa, int prefixlen)
{
int maxlen, i;
uint8_t *dst = sockany_addr(af, sa, &maxlen);
if (!dst) return 0;
sa->sa.sa_family = af;
if (prefixlen > 8*maxlen) prefixlen = 8*maxlen;
i = prefixlen / 8;
memset(dst, 0xff, i);
if (i<maxlen) {
dst[i++] = 0xff << (8 - (prefixlen % 8));
if (i<maxlen) memset(&dst[i+1], 0x00, maxlen-i);
}
return &sa->sa;
}
static int __handle_link(void *pctx, struct nlmsghdr *h)
{
struct ifaddrs_ctx *ctx = pctx;
struct ifaddrs_storage *ifs;
struct ifinfomsg *ifi = NLMSG_DATA(h);
struct rtattr *rta;
int stats_len = 0;
for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
if (rta->rta_type != IFLA_STATS) continue;
stats_len = RTA_DATALEN(rta);
break;
}
ifs = calloc(1, sizeof(struct ifaddrs_storage) + stats_len);
if (ifs == 0) return -1;
ifs->index = ifi->ifi_index;
ifs->ifa.ifa_flags = ifi->ifi_flags;
for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
switch (rta->rta_type) {
case IFLA_IFNAME:
if (RTA_DATALEN(rta) <= IFNAMSIZ) {
strncpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta));
ifs->ifa.ifa_name = ifs->name;
}
break;
case IFLA_ADDRESS:
ifs->ifa.ifa_addr = copy_lladdr(&ifs->addr, rta, ifi);
break;
case IFLA_BROADCAST:
ifs->ifa.ifa_broadaddr = copy_lladdr(&ifs->ifu, rta, ifi);
break;
case IFLA_STATS:
ifs->ifa.ifa_data = (void*)(ifs+1);
memcpy(ifs->ifa.ifa_data, RTA_DATA(rta), RTA_DATALEN(rta));
break;
}
}
if (ifs->ifa.ifa_name) {
ifs->hash_next = ctx->hash[ifs->index%IFADDRS_HASH_SIZE];
ctx->hash[ifs->index%IFADDRS_HASH_SIZE] = ifs;
}
addifaddrs(ctx, ifs);
return 0;
}
static int __handle_addr(void *pctx, struct nlmsghdr *h)
{
struct ifaddrs_ctx *ctx = pctx;
struct ifaddrs_storage *ifs, *ifs0;
struct ifaddrmsg *ifa = NLMSG_DATA(h);
struct rtattr *rta;
ifs = calloc(1, sizeof(struct ifaddrs_storage));
if (ifs == 0) return -1;
for (ifs0 = ctx->hash[ifa->ifa_index%IFADDRS_HASH_SIZE]; ifs0; ifs0 = ifs0->hash_next)
if (ifs0->index == ifa->ifa_index)
break;
if (!ifs0) return 0;
ifs->ifa.ifa_name = ifs0->ifa.ifa_name;
ifs->ifa.ifa_flags = ifs0->ifa.ifa_flags;
for (rta = NLMSG_RTA(h, sizeof(*ifa)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
switch (rta->rta_type) {
case IFA_ADDRESS:
ifs->ifa.ifa_addr = copy_addr(ifa->ifa_family, &ifs->addr, rta);
if (ifs->ifa.ifa_addr)
ifs->ifa.ifa_netmask = gen_netmask(ifa->ifa_family, &ifs->netmask, ifa->ifa_prefixlen);
break;
case IFA_BROADCAST:
/* For point-to-point links this is peer, but ifa_broadaddr
* and ifa_dstaddr are union, so this works for both. */
ifs->ifa.ifa_broadaddr = copy_addr(ifa->ifa_family, &ifs->ifu, rta);
break;
}
}
addifaddrs(ctx, ifs);
return 0;
}
int getifaddrs(struct ifaddrs **ifap)
{
struct ifaddrs_ctx _ctx, *ctx = &_ctx;
struct __netlink_handle *nh;
int r = 0;
nh = __netlink_open(NETLINK_ROUTE);
if (!nh) return -1;
memset(ctx, 0, sizeof(*ctx));
if (__netlink_enumerate(nh, RTM_GETLINK, __handle_link, ctx)) r = -1;
if (__netlink_enumerate(nh, RTM_GETADDR, __handle_addr, ctx)) r = -1;
__netlink_close(nh);
if (r == 0) *ifap = &ctx->first->ifa;
else freeifaddrs(&ctx->first->ifa);
return r;
}
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