1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
| | #define _GNU_SOURCE
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <syscall.h>
#include <net/if.h>
#include "__netlink.h"
/* getifaddrs() reports hardware addresses with PF_PACKET that implies
* struct sockaddr_ll. But e.g. Infiniband socket address length is
* longer than sockaddr_ll.ssl_addr[8] can hold. Use this hack struct
* to extend ssl_addr - callers should be able to still use it. */
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 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(void *pctx, struct nlmsghdr *h)
{
struct ifaddrs_ctx *ctx = pctx;
struct ifaddrs_storage *ifs, *ifs0;
struct ifinfomsg *ifi = NLMSG_DATA(h);
struct ifaddrmsg *ifa = NLMSG_DATA(h);
struct rtattr *rta;
int stats_len = 0;
if (h->nlmsg_type == RTM_NEWLINK) {
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;
}
} else {
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 = calloc(1, sizeof(struct ifaddrs_storage) + stats_len);
if (ifs == 0) return -1;
if (h->nlmsg_type == RTM_NEWLINK) {
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) < sizeof(ifs->name)) {
memcpy(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;
}
} else {
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;
case IFA_LABEL:
if (RTA_DATALEN(rta) < sizeof(ifs->name)) {
memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta));
ifs->ifa.ifa_name = ifs->name;
}
break;
}
}
}
if (ifs->ifa.ifa_name) {
if (!ctx->first) ctx->first = ifs;
if (ctx->last) ctx->last->ifa.ifa_next = &ifs->ifa;
ctx->last = ifs;
} else {
free(ifs);
}
return 0;
}
int getifaddrs(struct ifaddrs **ifap)
{
struct ifaddrs_ctx _ctx, *ctx = &_ctx;
int r;
memset(ctx, 0, sizeof *ctx);
r = __rtnetlink_enumerate(AF_UNSPEC, AF_UNSPEC, __handle, ctx);
if (r == 0) *ifap = &ctx->first->ifa;
else freeifaddrs(&ctx->first->ifa);
return r;
}
|