src/libsystemd-network/icmp6-packet.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <netinet/icmp6.h>
   4
   5 #include "icmp6-packet.h"
   6 #include "icmp6-util.h"
   7 #include "in-addr-util.h"
   8 #include "iovec-util.h"
   9 #include "network-common.h"
  10 #include "socket-util.h"
  11
  12 DEFINE_TRIVIAL_REF_UNREF_FUNC(ICMP6Packet, icmp6_packet, mfree);
  13
  14 static ICMP6Packet* icmp6_packet_new(size_t size) {
  15         ICMP6Packet *p;
  16
  17         if (size > SIZE_MAX - offsetof(ICMP6Packet, raw_packet))
  18                 return NULL;
  19
  20         p = malloc0(offsetof(ICMP6Packet, raw_packet) + size);
  21         if (!p)
  22                 return NULL;
  23
  24         p->raw_size = size;
  25         p->n_ref = 1;
  26
  27         return p;
  28 }
  29
  30 int icmp6_packet_get_sender_address(ICMP6Packet *p, struct in6_addr *ret) {
  31         assert(p);
  32
  33         if (in6_addr_is_null(&p->sender_address))
  34                 return -ENODATA;
  35
  36         if (ret)
  37                 *ret = p->sender_address;
  38         return 0;
  39 }
  40
  41 int icmp6_packet_get_timestamp(ICMP6Packet *p, clockid_t clock, usec_t *ret) {
  42         assert(p);
  43         assert(ret);
  44
  45         if (!TRIPLE_TIMESTAMP_HAS_CLOCK(clock) || !clock_supported(clock))
  46                 return -EOPNOTSUPP;
  47
  48         if (!triple_timestamp_is_set(&p->timestamp))
  49                 return -ENODATA;
  50
  51         *ret = triple_timestamp_by_clock(&p->timestamp, clock);
  52         return 0;
  53 }
  54
  55 const struct icmp6_hdr* icmp6_packet_get_header(ICMP6Packet *p) {
  56         assert(p);
  57
  58         if (p->raw_size < sizeof(struct icmp6_hdr))
  59                 return NULL;
  60
  61         return (const struct icmp6_hdr*) p->raw_packet;
  62 }
  63
  64 int icmp6_packet_get_type(ICMP6Packet *p) {
  65         const struct icmp6_hdr *hdr = icmp6_packet_get_header(p);
  66         if (!hdr)
  67                 return -EBADMSG;
  68
  69         return hdr->icmp6_type;
  70 }
  71
  72 static int icmp6_packet_verify(ICMP6Packet *p) {
  73         const struct icmp6_hdr *hdr = icmp6_packet_get_header(p);
  74         if (!hdr)
  75                 return -EBADMSG;
  76
  77         if (hdr->icmp6_code != 0)
  78                 return -EBADMSG;
  79
  80         return 0;
  81 }
  82
  83 int icmp6_packet_receive(int fd, ICMP6Packet **ret) {
  84         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *p = NULL;
  85         ssize_t len;
  86         int r;
  87
  88         assert(fd >= 0);
  89         assert(ret);
  90
  91         len = next_datagram_size_fd(fd);
  92         if (len < 0)
  93                 return (int) len;
  94
  95         p = icmp6_packet_new(len);
  96         if (!p)
  97                 return -ENOMEM;
  98
  99         r = icmp6_receive(fd, p->raw_packet, p->raw_size, &p->sender_address, &p->timestamp);
 100         if (r < 0)
 101                 switch (r) {
 102                 case -EADDRNOTAVAIL:
 103                         return log_debug_errno(r, "ICMPv6: Received a packet from neither link-local nor null address.");
 104
 105                 case -EMULTIHOP:
 106                         return log_debug_errno(r, "ICMPv6: Received a packet with an invalid hop limit.");
 107
 108                 case -EPFNOSUPPORT:
 109                         return log_debug_errno(r, "ICMPv6: Received a packet with an invalid source address.");
 110
 111                 default:
 112                         return log_debug_errno(r, "ICMPv6: Unexpected error while receiving a packet: %m");
 113                 }
 114
 115         r = icmp6_packet_verify(p);
 116         if (r < 0)
 117                 return r;
 118
 119         *ret = TAKE_PTR(p);
 120         return 0;
 121 }