Icmp6.cc
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1 /*
2  * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
3  *
4  * Squid software is distributed under GPLv2+ license and includes
5  * contributions from numerous individuals and organizations.
6  * Please see the COPYING and CONTRIBUTORS files for details.
7  */
8 
9 /* DEBUG: section 42 ICMP Pinger program */
10 
11 //#define SQUID_HELPER 1
12 
13 #include "squid.h"
14 
15 #if USE_ICMP
16 
17 #include "debug/Stream.h"
18 #include "Icmp6.h"
19 #include "IcmpPinger.h"
20 #include "time/gadgets.h"
21 
22 // Some system headers are only neeed internally here.
23 // They should not be included via the header.
24 
25 #if HAVE_NETINET_IP6_H
26 #include <netinet/ip6.h>
27 #endif
28 
29 // Icmp6 OP-Codes
30 // see http://www.iana.org/assignments/icmpv6-parameters
31 static const char *
32 IcmpPacketType(uint8_t v)
33 {
34  // NP: LowPktStr is for codes 0-127
35  static const char *icmp6LowPktStr[] = {
36  "ICMPv6 0", // 0
37  "Destination Unreachable", // 1 - RFC2463
38  "Packet Too Big", // 2 - RFC2463
39  "Time Exceeded", // 3 - RFC2463
40  "Parameter Problem", // 4 - RFC2463
41  };
42 
43  // low codes 1-4 registered
44  if (0 < v && v < 5)
45  return icmp6LowPktStr[(int)(v&0x7f)];
46 
47  // NP: HighPktStr is for codes 128-255
48  static const char *icmp6HighPktStr[] = {
49  "Echo Request", // 128 - RFC2463
50  "Echo Reply", // 129 - RFC2463
51  "Multicast Listener Query", // 130 - RFC2710
52  "Multicast Listener Report", // 131 - RFC2710
53  "Multicast Listener Done", // 132 - RFC2710
54  "Router Solicitation", // 133 - RFC4861
55  "Router Advertisement", // 134 - RFC4861
56  "Neighbor Solicitation", // 135 - RFC4861
57  "Neighbor Advertisement", // 136 - RFC4861
58  "Redirect Message", // 137 - RFC4861
59  "Router Renumbering", // 138 - Crawford
60  "ICMP Node Information Query", // 139 - RFC4620
61  "ICMP Node Information Response", // 140 - RFC4620
62  "Inverse Neighbor Discovery Solicitation", // 141 - RFC3122
63  "Inverse Neighbor Discovery Advertisement", // 142 - RFC3122
64  "Version 2 Multicast Listener Report", // 143 - RFC3810
65  "Home Agent Address Discovery Request", // 144 - RFC3775
66  "Home Agent Address Discovery Reply", // 145 - RFC3775
67  "Mobile Prefix Solicitation", // 146 - RFC3775
68  "Mobile Prefix Advertisement", // 147 - RFC3775
69  "Certification Path Solicitation", // 148 - RFC3971
70  "Certification Path Advertisement", // 149 - RFC3971
71  "ICMP Experimental (150)", // 150 - RFC4065
72  "Multicast Router Advertisement", // 151 - RFC4286
73  "Multicast Router Solicitation", // 152 - RFC4286
74  "Multicast Router Termination", // 153 - [RFC4286]
75  };
76 
77  // high codes 127-153 registered
78  if (127 < v && v < 154)
79  return icmp6HighPktStr[(int)(v&0x7f)];
80 
81  // give all others a generic display
82  static char buf[50];
83  snprintf(buf, sizeof(buf), "ICMPv6 %u", v);
84  return buf;
85 }
86 
88 {
89  ; // nothing new.
90 }
91 
93 {
94  Close();
95 }
96 
97 int
99 {
100  icmp_sock = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
101 
102  if (icmp_sock < 0) {
103  int xerrno = errno;
104  debugs(50, DBG_CRITICAL, MYNAME << " icmp_sock: " << xstrerr(xerrno));
105  return -1;
106  }
107 
108  icmp_ident = getpid() & 0xffff;
109  debugs(42, DBG_IMPORTANT, "ICMPv6 socket opened");
110 
111  return icmp_sock;
112 }
113 
117 void
118 Icmp6::SendEcho(Ip::Address &to, int opcode, const char *payload, int len)
119 {
120  int x;
121  LOCAL_ARRAY(char, pkt, MAX_PKT6_SZ);
122  struct icmp6_hdr *icmp = nullptr;
123  icmpEchoData *echo = nullptr;
124  struct addrinfo *S = nullptr;
125  size_t icmp6_pktsize = 0;
126 
127  static_assert(sizeof(*icmp) + sizeof(*echo) <= sizeof(pkt), "our custom ICMPv6 Echo payload fits the packet buffer");
128 
129  memset(pkt, '\0', MAX_PKT6_SZ);
130  icmp = (struct icmp6_hdr *)pkt;
131 
132  /*
133  * cevans - beware signed/unsigned issues in untrusted data from
134  * the network!!
135  */
136  if (len < 0) {
137  len = 0;
138  }
139 
140  // Construct Icmp6 ECHO header
141  icmp->icmp6_type = ICMP6_ECHO_REQUEST;
142  icmp->icmp6_code = 0;
143  icmp->icmp6_cksum = 0;
144  icmp->icmp6_id = icmp_ident;
145  icmp->icmp6_seq = (unsigned short) icmp_pkts_sent;
146  ++icmp_pkts_sent;
147 
148  icmp6_pktsize = sizeof(struct icmp6_hdr);
149 
150  // Fill Icmp6 ECHO data content
151  echo = reinterpret_cast<icmpEchoData *>(reinterpret_cast<char *>(pkt) + sizeof(*icmp));
152  echo->opcode = (unsigned char) opcode;
153  memcpy(&echo->tv, &current_time, sizeof(struct timeval));
154 
155  icmp6_pktsize += sizeof(struct timeval) + sizeof(char);
156 
157  if (payload) {
158  if (len > MAX_PAYLOAD)
159  len = MAX_PAYLOAD;
160 
161  memcpy(echo->payload, payload, len);
162 
163  icmp6_pktsize += len;
164  }
165 
166  icmp->icmp6_cksum = CheckSum((unsigned short *) icmp, icmp6_pktsize);
167 
168  to.getAddrInfo(S);
169  ((sockaddr_in6*)S->ai_addr)->sin6_port = 0;
170 
171  assert(icmp6_pktsize <= MAX_PKT6_SZ);
172 
173  debugs(42, 5, "Send Icmp6 packet to " << to << ".");
174 
175  x = sendto(icmp_sock,
176  (const void *) pkt,
177  icmp6_pktsize,
178  0,
179  S->ai_addr,
180  S->ai_addrlen);
181 
182  if (x < 0) {
183  int xerrno = errno;
184  debugs(42, DBG_IMPORTANT, MYNAME << "ERROR: sending to ICMPv6 packet to " << to << ": " << xstrerr(xerrno));
185  }
186  debugs(42,9, "x=" << x);
187 
188  Log(to, 0, nullptr, 0, 0);
190 }
191 
195 void
197 {
198  int n;
199  struct addrinfo *from = nullptr;
200 // struct ip6_hdr *ip = NULL;
201  static char *pkt = nullptr;
202  struct icmp6_hdr *icmp6header = nullptr;
203  icmpEchoData *echo = nullptr;
204  struct timeval now;
205  static pingerReplyData preply;
206 
207  if (icmp_sock < 0) {
208  debugs(42, DBG_CRITICAL, "dropping ICMPv6 read. No socket!?");
209  return;
210  }
211 
212  if (pkt == nullptr) {
213  pkt = (char *)xmalloc(MAX_PKT6_SZ);
214  }
215 
216  Ip::Address::InitAddr(from);
217 
218  n = recvfrom(icmp_sock,
219  (void *)pkt,
220  MAX_PKT6_SZ,
221  0,
222  from->ai_addr,
223  &from->ai_addrlen);
224 
225  if (n <= 0) {
226  debugs(42, DBG_CRITICAL, "ERROR: when calling recvfrom() on ICMPv6 socket.");
227  Ip::Address::FreeAddr(from);
228  return;
229  }
230 
231  preply.from = *from;
232 
233 #if GETTIMEOFDAY_NO_TZP
234 
235  gettimeofday(&now);
236 
237 #else
238 
239  gettimeofday(&now, nullptr);
240 
241 #endif
242 
243  debugs(42, 8, n << " bytes from " << preply.from);
244 
245 // XXX: The IPv6 Header (ip6_hdr) is not available directly
246 //
247 // TTL still has to come from the IP header somewhere.
248 // still need to strip and process it properly.
249 // probably have to rely on RTT as given by timestamp in data sent and current.
250  /* IPv6 Header Structures (linux)
251  struct ip6_hdr
252 
253  // fields (via simple define)
254  #define ip6_vfc // N.A
255  #define ip6_flow // N/A
256  #define ip6_plen // payload length.
257  #define ip6_nxt // expect to be type 0x3a - ICMPv6
258  #define ip6_hlim // MAX hops (always 64, but no guarantee)
259  #define ip6_hops // HOPS!!! (can it be true??)
260 
261  ip = (struct ip6_hdr *) pkt;
262  // += sizeof(ip6_hdr);
263 
264  debugs(42, DBG_CRITICAL, "ip6_nxt=" << ip->ip6_nxt <<
265  ", ip6_plen=" << ip->ip6_plen <<
266  ", ip6_hlim=" << ip->ip6_hlim <<
267  ", ip6_hops=" << ip->ip6_hops <<
268  " ::: 40 == sizef(ip6_hdr) == " << sizeof(ip6_hdr)
269  );
270  */
271 
272  icmp6header = (struct icmp6_hdr *) pkt;
273 
274  if (icmp6header->icmp6_type != ICMP6_ECHO_REPLY) {
275 
276  switch (icmp6header->icmp6_type) {
277  case 134:
278  case 135:
279  case 136:
280  /* ignore Router/Neighbour Advertisements */
281  break;
282 
283  default:
284  debugs(42, 8, preply.from << " said: " << icmp6header->icmp6_type << "/" << (int)icmp6header->icmp6_code << " " <<
285  IcmpPacketType(icmp6header->icmp6_type));
286  }
287  Ip::Address::FreeAddr(from);
288  return;
289  }
290 
291  if (icmp6header->icmp6_id != icmp_ident) {
292  debugs(42, 8, "dropping Icmp6 read. IDENT check failed. ident=='" << icmp_ident << "'=='" << icmp6header->icmp6_id << "'");
293  Ip::Address::FreeAddr(from);
294  return;
295  }
296 
297  echo = (icmpEchoData *) (pkt + sizeof(icmp6_hdr));
298 
299  preply.opcode = echo->opcode;
300 
301  struct timeval tv;
302  memcpy(&tv, &echo->tv, sizeof(struct timeval));
303  preply.rtt = tvSubMsec(tv, now);
304 
305  /*
306  * Without access to the IPv6-Hops header we must rely on the total RTT
307  * and could calculate the hops from that, but it produces some weird value mappings using ipHops
308  * for now everything is 1 v6 hop away with variant RTT
309  * WANT: preply.hops = ip->ip6_hops; // ipHops(ip->ip_hops);
310  */
311  preply.hops = 1;
312 
313  preply.psize = n - /* sizeof(ip6_hdr) - */ sizeof(icmp6_hdr) - (sizeof(icmpEchoData) - MAX_PKT6_SZ);
314 
315  /* Ensure the response packet has safe payload size */
316  if ( preply.psize > (unsigned short) MAX_PKT6_SZ) {
317  preply.psize = MAX_PKT6_SZ;
318  } else if ( preply.psize < (unsigned short)0) {
319  preply.psize = 0;
320  }
321 
322  Log(preply.from,
323  icmp6header->icmp6_type,
324  IcmpPacketType(icmp6header->icmp6_type),
325  preply.rtt,
326  preply.hops);
327 
328  /* send results of the lookup back to squid.*/
329  control.SendResult(preply, (sizeof(pingerReplyData) - PINGER_PAYLOAD_SZ + preply.psize) );
330  Ip::Address::FreeAddr(from);
331 }
332 
333 #endif /* USE_ICMP */
334 
static const char * IcmpPacketType(uint8_t v)
Definition: Icmp6.cc:32
#define IPPROTO_ICMPV6
Definition: Icmp6.h:38
IcmpPinger control
pinger helper contains one of these as a global object.
Definition: pinger.cc:90
#define PINGER_PAYLOAD_SZ
Definition: Icmp.h:16
int icmp_pkts_sent
Definition: pinger.cc:94
#define MAX_PKT6_SZ
Definition: Icmp.h:20
#define MAX_PAYLOAD
Definition: Icmp.h:18
#define assert(EX)
Definition: assert.h:19
Icmp6()
Definition: Icmp6.cc:87
virtual ~Icmp6()
Definition: Icmp6.cc:92
virtual void Recv(void)
Definition: Icmp6.cc:196
virtual int Open()
Start pinger helper and initiate control channel.
Definition: Icmp6.cc:98
virtual void SendEcho(Ip::Address &, int, const char *, int)
Definition: Icmp6.cc:118
void SendResult(pingerReplyData &preply, int len)
Send ICMP results back to squid.
Definition: IcmpPinger.cc:218
Definition: Icmp.h:68
virtual void Close()
Shutdown pinger helper and control channel.
Definition: Icmp.cc:25
int CheckSum(unsigned short *ptr, int size)
Calculate a packet checksum.
Definition: Icmp.cc:38
int icmp_ident
Definition: Icmp.h:122
void Log(const Ip::Address &addr, const uint8_t type, const char *pkt_str, const int rtt, const int hops)
Log the packet.
Definition: Icmp.cc:88
int icmp_sock
Definition: Icmp.h:121
static void InitAddr(struct addrinfo *&ai)
Definition: Address.cc:668
static void FreeAddr(struct addrinfo *&ai)
Definition: Address.cc:686
void getAddrInfo(struct addrinfo *&ai, int force=AF_UNSPEC) const
Definition: Address.cc:599
#define MYNAME
Definition: Stream.h:238
#define DBG_IMPORTANT
Definition: Stream.h:41
#define debugs(SECTION, LEVEL, CONTENT)
Definition: Stream.h:196
#define DBG_CRITICAL
Definition: Stream.h:40
#define xmalloc
#define LOCAL_ARRAY(type, name, size)
Definition: squid.h:75
struct sockaddr * ai_addr
socklen_t ai_addrlen
char payload[MAX_PAYLOAD]
Definition: Icmp.h:48
unsigned char opcode
Definition: Icmp.h:47
struct timeval tv
Definition: Icmp.h:46
int unsigned int
Definition: stub_fd.cc:19
static struct timeval now
Definition: tcp-banger2.c:97
struct timeval current_time
the current UNIX time in timeval {seconds, microseconds} format
Definition: gadgets.cc:17
int tvSubMsec(struct timeval t1, struct timeval t2)
Definition: gadgets.cc:51
const char * xstrerr(int error)
Definition: xstrerror.cc:83

 

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