libnl  3.5.0
mpls.c
1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3  * Adapted from mpls_ntop and mpls_pton copied from iproute2,
4  * lib/mpls_ntop.c and lib/mpls_pton.c
5  */
6 #include <errno.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <netinet/in.h>
10 #include <netlink/netlink-compat.h>
11 #include <netlink-private/route/mpls.h>
12 #include <linux-private/linux/mpls.h>
13 
14 static const char *mpls_ntop1(const struct mpls_label *addr,
15  char *buf, size_t buflen)
16 {
17  size_t destlen = buflen;
18  char *dest = buf;
19  int count = 0;
20 
21  while (1) {
22  uint32_t entry = ntohl(addr[count++].entry);
23  uint32_t label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
24  int len = snprintf(dest, destlen, "%u", label);
25 
26  if (len >= destlen)
27  break;
28 
29  /* Is this the end? */
30  if (entry & MPLS_LS_S_MASK)
31  return buf;
32 
33  dest += len;
34  destlen -= len;
35  if (destlen) {
36  *dest = '/';
37  dest++;
38  destlen--;
39  }
40  }
41  errno = E2BIG;
42 
43  return NULL;
44 }
45 
46 const char *mpls_ntop(int af, const void *addr, char *buf, size_t buflen)
47 {
48  switch(af) {
49  case AF_MPLS:
50  errno = 0;
51  return mpls_ntop1((struct mpls_label *)addr, buf, buflen);
52  }
53 
54  errno = EINVAL;
55  return NULL;
56 }
57 
58 static int mpls_pton1(const char *name, struct mpls_label *addr,
59  unsigned int maxlabels)
60 {
61  char *endp;
62  unsigned count;
63 
64  for (count = 0; count < maxlabels; count++) {
65  unsigned long label;
66 
67  label = strtoul(name, &endp, 0);
68  /* Fail when the label value is out or range */
69  if (label >= (1 << 20))
70  return 0;
71 
72  if (endp == name) /* no digits */
73  return 0;
74 
75  addr->entry = htonl(label << MPLS_LS_LABEL_SHIFT);
76  if (*endp == '\0') {
77  addr->entry |= htonl(1 << MPLS_LS_S_SHIFT);
78  return (count + 1) * sizeof(struct mpls_label);
79  }
80 
81  /* Bad character in the address */
82  if (*endp != '/')
83  return 0;
84 
85  name = endp + 1;
86  addr += 1;
87  }
88 
89  /* The address was too long */
90  return 0;
91 }
92 
93 int mpls_pton(int af, const char *src, void *addr, size_t alen)
94 {
95  unsigned int maxlabels = alen / sizeof(struct mpls_label);
96  int err;
97 
98  switch(af) {
99  case AF_MPLS:
100  errno = 0;
101  err = mpls_pton1(src, (struct mpls_label *)addr, maxlabels);
102  break;
103  default:
104  errno = EAFNOSUPPORT;
105  err = -1;
106  }
107 
108  return err;
109 }