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_set_sender_address(ICMP6Packet *p, const struct in6_addr *addr) {
  31         assert(p);
  32
  33         if (addr)
  34                 p->sender_address = *addr;
  35         else
  36                 p->sender_address = (const struct in6_addr) {};
  37
  38         return 0;
  39 }
  40
  41 int icmp6_packet_get_sender_address(ICMP6Packet *p, struct in6_addr *ret) {
  42         assert(p);
  43
  44         if (in6_addr_is_null(&p->sender_address))
  45                 return -ENODATA;
  46
  47         if (ret)
  48                 *ret = p->sender_address;
  49         return 0;
  50 }
  51
  52 int icmp6_packet_get_timestamp(ICMP6Packet *p, clockid_t clock, usec_t *ret) {
  53         assert(p);
  54         assert(ret);
  55
  56         if (!TRIPLE_TIMESTAMP_HAS_CLOCK(clock) || !clock_supported(clock))
  57                 return -EOPNOTSUPP;
  58
  59         if (!triple_timestamp_is_set(&p->timestamp))
  60                 return -ENODATA;
  61
  62         *ret = triple_timestamp_by_clock(&p->timestamp, clock);
  63         return 0;
  64 }
  65
  66 const struct icmp6_hdr* icmp6_packet_get_header(ICMP6Packet *p) {
  67         assert(p);
  68
  69         if (p->raw_size < sizeof(struct icmp6_hdr))
  70                 return NULL;
  71
  72         return (const struct icmp6_hdr*) p->raw_packet;
  73 }
  74
  75 int icmp6_packet_get_type(ICMP6Packet *p) {
  76         const struct icmp6_hdr *hdr = icmp6_packet_get_header(p);
  77         if (!hdr)
  78                 return -EBADMSG;
  79
  80         return hdr->icmp6_type;
  81 }
  82
  83 static int icmp6_packet_verify(ICMP6Packet *p) {
  84         const struct icmp6_hdr *hdr = icmp6_packet_get_header(p);
  85         if (!hdr)
  86                 return -EBADMSG;
  87
  88         if (hdr->icmp6_code != 0)
  89                 return -EBADMSG;
  90
  91         /* Drop any overly large packets early. We are not interested in jumbograms,
  92          * which could cause excessive processing. */
  93         if (p->raw_size > ICMP6_MAX_NORMAL_PAYLOAD_SIZE)
  94                 return -EMSGSIZE;
  95
  96         return 0;
  97 }
  98
  99 int icmp6_packet_receive(int fd, ICMP6Packet **ret) {
 100         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *p = NULL;
 101         ssize_t len;
 102         int r;
 103
 104         assert(fd >= 0);
 105         assert(ret);
 106
 107         len = next_datagram_size_fd(fd);
 108         if (len < 0)
 109                 return (int) len;
 110
 111         p = icmp6_packet_new(len);
 112         if (!p)
 113                 return -ENOMEM;
 114
 115         r = icmp6_receive(fd, p->raw_packet, p->raw_size, &p->sender_address, &p->timestamp);
 116         if (r == -EADDRNOTAVAIL)
 117                 return log_debug_errno(r, "ICMPv6: Received a packet from neither link-local nor null address.");
 118         if (r == -EMULTIHOP)
 119                 return log_debug_errno(r, "ICMPv6: Received a packet with an invalid hop limit.");
 120         if (r == -EPFNOSUPPORT)
 121                 return log_debug_errno(r, "ICMPv6: Received a packet with an invalid source address.");
 122         if (r < 0)
 123                 return log_debug_errno(r, "ICMPv6: Unexpected error while receiving a packet: %m");
 124
 125         r = icmp6_packet_verify(p);
 126         if (r < 0)
 127                 return r;
 128
 129         *ret = TAKE_PTR(p);
 130         return 0;
 131 }