obgm · obgm · Sep 8, 2020 · Jun 15, 2020
diff --git a/Makefile.am b/Makefile.am
@@ -174,9 +174,11 @@ coap_dtls_session_update_mtu \
 coap_dtls_shutdown \
 coap_dtls_startup \
 coap_epoll_ctl_mod \
+coap_insert_option \
 coap_io_do_events \
 coap_mfree_endpoint \
 coap_packet_extract_pbuf \
+coap_pdu_check_resize \
 coap_pdu_from_pbuf \
 coap_session_mfree \
 coap_session_new_dtls_session \
@@ -199,6 +201,7 @@ coap_tls_new_client_session \
 coap_tls_new_server_session \
 coap_tls_read \
 coap_tls_write \
+coap_update_option \
 "
 
 # This helper is called by libcoap-$(LIBCOAP_API_VERSION).{map,sym} to see if

diff --git a/README.md b/README.md
@@ -48,6 +48,9 @@ The following RFCs are supported
 * RFC8132: PATCH and FETCH Methods for the Constrained Application Protocol (CoAP)
 
 * RFC8323: CoAP (Constrained Application Protocol) over TCP, TLS, and WebSockets
+  [No WebSockets support]
+
+* RFC8768: Constrained Application Protocol (CoAP) Hop-Limit Option
 
 There is (D)TLS support for the following libraries
 

diff --git a/examples/client.c b/examples/client.c
@@ -251,15 +251,16 @@ clear_obs(coap_context_t *ctx, coap_session_t *session) {
 
   for (option = optlist; option; option = option->next ) {
     switch (option->number) {
-    case COAP_OPTION_URI_PORT :
-    case COAP_OPTION_URI_PATH :
-    case COAP_OPTION_URI_QUERY :
+    case COAP_OPTION_URI_PORT :  /*  7 */
+    case COAP_OPTION_URI_PATH :  /* 11 */
+    case COAP_OPTION_URI_QUERY : /* 15 */
+    case COAP_OPTION_HOP_LIMIT : /* 16 */
       if (!coap_add_option(pdu, option->number, option->length,
                            option->data)) {
         goto error;
       }
       break;
-      default:
+    default:
       ;
     }
   }
@@ -453,13 +454,14 @@ message_handler(struct coap_context_t *ctx,
         /* create pdu with request for next block */
         pdu = coap_new_request(ctx, session, method, NULL, NULL, 0); /* first, create bare PDU w/o any option  */
         if ( pdu ) {
-          /* add URI components from optlist */
+          /* add URI components from optlist in ascending order */
           for (option = optlist; option; option = option->next ) {
             switch (option->number) {
-              case COAP_OPTION_URI_HOST :
-              case COAP_OPTION_URI_PORT :
-              case COAP_OPTION_URI_PATH :
-              case COAP_OPTION_URI_QUERY :
+              case COAP_OPTION_URI_HOST :  /*  3 */
+              case COAP_OPTION_URI_PORT :  /*  7 */
+              case COAP_OPTION_URI_PATH :  /* 11 */
+              case COAP_OPTION_URI_QUERY : /* 15 */
+              case COAP_OPTION_HOP_LIMIT : /* 16 */
                 coap_add_option(pdu, option->number, option->length,
                                 option->data);
                 break;
@@ -550,11 +552,12 @@ message_handler(struct coap_context_t *ctx,
           /* add URI components from optlist */
           for (option = optlist; option; option = option->next ) {
             switch (option->number) {
-              case COAP_OPTION_URI_HOST :
-              case COAP_OPTION_URI_PORT :
-              case COAP_OPTION_URI_PATH :
-              case COAP_OPTION_CONTENT_FORMAT :
-              case COAP_OPTION_URI_QUERY :
+              case COAP_OPTION_URI_HOST :       /*  3 */
+              case COAP_OPTION_URI_PORT :       /*  7 */
+              case COAP_OPTION_URI_PATH :       /* 11 */
+              case COAP_OPTION_CONTENT_FORMAT : /* 12 */
+              case COAP_OPTION_URI_QUERY :      /* 15 */
+              case COAP_OPTION_HOP_LIMIT :      /* 16 */
                 coap_add_option(pdu, option->number, option->length,
                                 option->data);
                 break;
@@ -641,8 +644,8 @@ usage( const char *program, const char *version) {
      "%s\n\n"
      "Usage: %s [-a addr] [-b [num,]size] [-e text] [-f file] [-l loss]\n"
      "\t\t[-m method] [-o file] [-p port] [-r] [-s duration] [-t type]\n"
-     "\t\t[-v num] [-A type] [-B seconds] [-K interval] [-N] [-O num,text]\n"
-     "\t\t[-P addr[:port]] [-T token] [-U]\n"
+     "\t\t[-v num] [-A type] [-B seconds] [-H hoplimit] [-K interval] [-N]\n"
+     "\t\t[-O num,text] [-P addr[:port]] [-T token] [-U]\n"
      "\t\t[[-h match_hint_file] [-k key] [-u user]]\n"
      "\t\t[[-c certfile] [-j keyfile] [-C cafile] [-J pkcs11_pin]\n"
      "\t\t[-R root_cafile] [-S match_pki_sni_file]] URI\n"
@@ -674,6 +677,9 @@ usage( const char *program, const char *version) {
      "\t-A type\t\tAccepted media type\n"
      "\t-B seconds\tBreak operation after waiting given seconds\n"
      "\t       \t\t(default is %d)\n"
+     "\t-H hoplimit\tSet the Hop Limit count to hoplimit for proxies. Must\n"
+     "\t       \t\thave a value between 1 and 255 inclusive.\n"
+     "\t       \t\tDefault is '16'\n"
      "\t-K interval\tsend a ping after interval seconds of inactivity\n"
      "\t-N     \t\tSend NON-confirmable message\n"
      "\t-O num,text\tAdd option num with contents text to request. If the\n"
@@ -722,7 +728,8 @@ usage( const char *program, const char *version) {
      "\t       \t\t'trusted' for the verification.\n"
      "\t       \t\tAlternatively, this can point to a directory containing\n"
      "\t       \t\ta set of CA PEM files\n"
-     "\n"
+     );
+  fprintf( stderr,
      "Examples:\n"
      "\tcoap-client -m get coap://[::1]/\n"
      "\tcoap-client -m get coap://[::1]/.well-known/core\n"
@@ -788,6 +795,24 @@ cmdline_content_type(char *arg, uint16_t key) {
   }
 }
 
+static int
+cmdline_hop_limit(char *arg) {
+  coap_optlist_t *node;
+  uint32_t value;
+  uint8_t buf[4];
+
+  value = strtol(arg, NULL, 10);
+  if (value < 1 || value > 255) {
+    return 0;
+  }
+  node = coap_new_optlist(COAP_OPTION_HOP_LIMIT, coap_encode_var_safe(buf, sizeof(buf), value), buf);
+  if (node) {
+    coap_insert_optlist(&optlist, node);
+  }
+  return 1;
+}
+
+
 static uint16_t
 get_default_port(const coap_uri_t *u) {
   return coap_uri_scheme_is_secure(u) ? COAPS_DEFAULT_PORT : COAP_DEFAULT_PORT;
@@ -1533,7 +1558,7 @@ main(int argc, char **argv) {
   struct sigaction sa;
 #endif
 
-  while ((opt = getopt(argc, argv, "a:b:c:e:f:h:j:k:l:m:o:p:rs:t:u:v:A:B:C:J:K:NO:P:R:T:U")) != -1) {
+  while ((opt = getopt(argc, argv, "a:b:c:e:f:h:j:k:l:m:o:p:rs:t:u:v:A:B:C:J:K:H:NO:P:R:T:U")) != -1) {
     switch (opt) {
     case 'a':
       strncpy(node_str, optarg, NI_MAXHOST - 1);
@@ -1643,6 +1668,10 @@ main(int argc, char **argv) {
         exit(1);
       }
       break;
+    case 'H':
+      if (!cmdline_hop_limit(optarg))
+        fprintf(stderr, "Hop Limit has to be > 0 and < 256\n");
+      break;
     default:
       usage( argv[0], LIBCOAP_PACKAGE_VERSION );
       exit( 1 );

diff --git a/include/coap2/pdu.h b/include/coap2/pdu.h
@@ -32,6 +32,10 @@ struct coap_session_t;
 #define COAP_DEFAULT_MTU       1152
 #endif /* COAP_DEFAULT_MTU */
 
+#ifndef COAP_DEFAULT_HOP_LIMIT
+#define COAP_DEFAULT_HOP_LIMIT       16
+#endif /* COAP_DEFAULT_HOP_LIMIT */
+
 /* TCP Message format constants, do not modify */
 #define COAP_MESSAGE_SIZE_OFFSET_TCP8 13
 #define COAP_MESSAGE_SIZE_OFFSET_TCP16 269 /* 13 + 256 */
@@ -87,41 +91,60 @@ typedef enum coap_request_t {
 } coap_request_t;
 
 /*
- * CoAP option types (be sure to update coap_option_check_critical() when
- * adding options
+ * CoAP option types (be sure to update coap_option_check_critical() and
+ * coap_add_option() when adding options
  */
 
-#define COAP_OPTION_IF_MATCH        1 /* C, opaque, 0-8 B, (none) */
-#define COAP_OPTION_URI_HOST        3 /* C, String, 1-255 B, destination address */
-#define COAP_OPTION_ETAG            4 /* E, opaque, 1-8 B, (none) */
-#define COAP_OPTION_IF_NONE_MATCH   5 /* empty, 0 B, (none) */
-#define COAP_OPTION_URI_PORT        7 /* C, uint, 0-2 B, destination port */
-#define COAP_OPTION_LOCATION_PATH   8 /* E, String, 0-255 B, - */
-#define COAP_OPTION_URI_PATH       11 /* C, String, 0-255 B, (none) */
-#define COAP_OPTION_CONTENT_FORMAT 12 /* E, uint, 0-2 B, (none) */
-#define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
-#define COAP_OPTION_MAXAGE         14 /* E, uint, 0--4 B, 60 Seconds */
-#define COAP_OPTION_URI_QUERY      15 /* C, String, 1-255 B, (none) */
-#define COAP_OPTION_ACCEPT         17 /* C, uint,   0-2 B, (none) */
-#define COAP_OPTION_LOCATION_QUERY 20 /* E, String,   0-255 B, (none) */
-#define COAP_OPTION_SIZE2          28 /* E, uint, 0-4 B, (none) */
-#define COAP_OPTION_PROXY_URI      35 /* C, String, 1-1034 B, (none) */
-#define COAP_OPTION_PROXY_SCHEME   39 /* C, String, 1-255 B, (none) */
-#define COAP_OPTION_SIZE1          60 /* E, uint, 0-4 B, (none) */
-
-/* option types from RFC 7641 */
-
-#define COAP_OPTION_OBSERVE         6 /* E, empty/uint, 0 B/0-3 B, (none) */
-#define COAP_OPTION_SUBSCRIPTION  COAP_OPTION_OBSERVE
-
-/* selected option types from RFC 7959 */
-
-#define COAP_OPTION_BLOCK2         23 /* C, uint, 0--3 B, (none) */
-#define COAP_OPTION_BLOCK1         27 /* C, uint, 0--3 B, (none) */
-
-/* selected option types from RFC 7967 */
+/*
+ * The C, U, and N flags indicate the properties
+ * Critical, Unsafe, and NoCacheKey, respectively.
+ * If U is set, then N has no meaning as per
+ * https://tools.ietf.org/html/rfc7252#section-5.10
+ * and is set to a -.
+ *
+ * Separately, R is for the options that can be repeated
+ *
+ * The least significant byte of the option is set as followed
+ * as per https://tools.ietf.org/html/rfc7252#section-5.4.6
+ *
+ *   0   1   2   3   4   5   6   7
+ * --+---+---+---+---+---+---+---+
+ *           | NoCacheKey| U | C |
+ * --+---+---+---+---+---+---+---+
+ *
+ * https://tools.ietf.org/html/rfc8613#section-4 goes on to define E, I and U
+ * properties Encrypted and Integrity Protected, Integrity Protected Only and
+ * Unprotected respectively.  Integretity Protected Only is not currently used.
+ *
+ * An Option is tagged with CUNREIU with any of the letters replaced with _ if
+ * not set, or - for N if U is set (see above) for aiding understanding of the
+ * Option.
+ */
 
-#define COAP_OPTION_NORESPONSE    258 /* N, uint, 0--1 B, 0 */
+#define COAP_OPTION_IF_MATCH        1 /* C__RE__, opaque,    0-8 B, RFC7252 */
+#define COAP_OPTION_URI_HOST        3 /* CU-___U, String,  1-255 B, RFC7252 */
+#define COAP_OPTION_ETAG            4 /* ___RE__, opaque,    1-8 B, RFC7252 */
+#define COAP_OPTION_IF_NONE_MATCH   5 /* C___E__, empty,       0 B, RFC7252 */
+#define COAP_OPTION_OBSERVE         6 /* _U-_E_U, empty/uint,0/0-3 B, RFC7641 */
+#define COAP_OPTION_URI_PORT        7 /* CU-___U, uint,      0-2 B, RFC7252 */
+#define COAP_OPTION_LOCATION_PATH   8 /* ___RE__, String,  0-255 B, RFC7252 */
+#define COAP_OPTION_OSCORE          9 /* C_____U, *,       0-255 B, RFC8613 */
+#define COAP_OPTION_URI_PATH       11 /* CU-RE__, String,  0-255 B, RFC7252 */
+#define COAP_OPTION_CONTENT_FORMAT 12 /* ____E__, uint,      0-2 B, RFC7252 */
+#define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
+/* COAP_OPTION_MAXAGE default 60 seconds if not set */
+#define COAP_OPTION_MAXAGE         14 /* _U-_E_U, uint,      0-4 B, RFC7252 */
+#define COAP_OPTION_URI_QUERY      15 /* CU-RE__, String,  1-255 B, RFC7252 */
+#define COAP_OPTION_HOP_LIMIT      16 /* ______U, uint,        1 B, RFC8768 */
+#define COAP_OPTION_ACCEPT         17 /* C___E__, uint,      0-2 B, RFC7252 */
+#define COAP_OPTION_LOCATION_QUERY 20 /* ___RE__, String,  0-255 B, RFC7252 */
+#define COAP_OPTION_BLOCK2         23 /* CU-_E_U, uint,      0-3 B, RFC7959 */
+#define COAP_OPTION_BLOCK1         27 /* CU-_E_U, uint,      0-3 B, RFC7959 */
+#define COAP_OPTION_SIZE2          28 /* __N_E_U, uint,      0-4 B, RFC7959 */
+#define COAP_OPTION_PROXY_URI      35 /* CU-___U, String, 1-1034 B, RFC7252 */
+#define COAP_OPTION_PROXY_SCHEME   39 /* CU-___U, String,  1-255 B, RFC7252 */
+#define COAP_OPTION_SIZE1          60 /* __N_E_U, uint,      0-4 B, RFC7252 */
+#define COAP_OPTION_NORESPONSE    258 /* _U-_E_U, uint,      0-1 B, RFC7967 */
 
 #define COAP_MAX_OPT            65535 /**< the highest option number we know */
 
@@ -273,7 +296,7 @@ typedef struct coap_pdu_t {
   uint8_t type;             /**< message type */
   uint8_t code;             /**< request method (value 1--31) or response code (value 64-255) */
   uint8_t max_hdr_size;     /**< space reserved for protocol-specific header */
-  uint8_t hdr_size;         /**< actaul size used for protocol-specific header */
+  uint8_t hdr_size;         /**< actual size used for protocol-specific header */
   uint8_t token_length;     /**< length of Token */
   uint16_t tid;             /**< transaction id, if any, in regular host byte order */
   uint16_t max_delta;       /**< highest option number */
@@ -359,6 +382,19 @@ coap_pdu_init(uint8_t type, uint8_t code, uint16_t tid, size_t size);
  */
 int coap_pdu_resize(coap_pdu_t *pdu, size_t new_size);
 
+/**
+ * Dynamically grows the size of @p pdu to @p new_size if needed. The new size
+ * must not exceed the PDU's configure maximum size. On success, this
+ * function returns 1, otherwise 0.
+ *
+ * Internal use only.
+ *
+ * @param pdu      The PDU to resize.
+ * @param new_size The new size in bytes.
+ * @return         1 if the operation succeeded, 0 otherwise.
+ */
+int coap_pdu_check_resize(coap_pdu_t *pdu, size_t new_size);
+
 /**
  * Clears any contents from @p pdu and resets @c used_size,
  * and @c data pointers. @c max_size is set to @p size, any
@@ -489,6 +525,25 @@ uint8_t *coap_add_option_later(coap_pdu_t *pdu,
                                uint16_t type,
                                size_t len);
 
+
+/**
+ * Inserts option of given type in the @p pdu with the appropriate data.
+ * The option will be inserted in the appropriate place in the options in the pdu.
+ *
+ * Internal use only.
+ */
+size_t coap_insert_option(coap_pdu_t *pdu, uint16_t type,
+                          size_t len, const uint8_t *data);
+
+/**
+ * Updates existing first option of given type in the @p pdu with the new data.
+ *
+ * Internal use only.
+ */
+int coap_update_option(coap_pdu_t *pdu,
+                       uint16_t type,
+                       size_t len,
+                       const uint8_t *data);
 /**
  * Adds given data to the pdu that is passed as first parameter. Note that the
  * PDU's data is destroyed by coap_add_option(). coap_add_data() must be called
@@ -500,7 +555,7 @@ int coap_add_data(coap_pdu_t *pdu,
 
 /**
  * Adds given data to the pdu that is passed as first parameter but does not
- * copyt it. Note that the PDU's data is destroyed by coap_add_option().
+ * copy it. Note that the PDU's data is destroyed by coap_add_option().
  * coap_add_data() must be have been called once for this PDU, otherwise the
  * result is undefined.
  * The actual data must be copied at the returned location.

diff --git a/man/coap-client.txt.in b/man/coap-client.txt.in
@@ -16,8 +16,9 @@ SYNOPSIS
 --------
 *coap-client* [*-a* addr] [*-b* [num,]size] [*-e* text] [*-f* file] [*-l* loss]
               [*-m* method] [*-o* file] [*-p* port] [*-r*] [*-s duration*]
-              [*-t* type] [*-v* num] [*-A* type] [*-B* seconds] [*-K* interval]
-              [*-N*] [*-O* num,text] [*-P* addr[:port]] [*-T* token] [*-U*]
+              [*-t* type] [*-v* num] [*-A* type] [*-B* seconds]
+              [*-H* hoplimit] [*-K* interval] [*-N*] [*-O* num,text]
+              [*-P* addr[:port]] [*-T* token] [*-U*]
               [[*-h* match_hint_file] [*-k* key] [*-u* user]]
               [[*-c* certfile] [*-j* keyfile] [*-C* cafile] [*-J* pkcs11_pin]
               [*-R* root_cafile]] URI
@@ -109,6 +110,10 @@ OPTIONS - General
 *-B* seconds::
    Break operation after waiting given seconds (default is 90).
 
+*-H* hoplimit::
+   Set the Hop Limit count to hoplimit for proxies. Must have a value between
+   1 and 255 inclusive. Default is '16'.
+
 *-K* interval::
    Send a ping after interval seconds of inactivity.
    If not specified (or 0), keep-alive is disabled (default).

diff --git a/man/coap.txt.in b/man/coap.txt.in
@@ -61,6 +61,8 @@ See
 
 "RFC8323: CoAP (Constrained Application Protocol) over TCP, TLS, and WebSockets"
 
+"RFC8768: Constrained Application Protocol (CoAP) Hop-Limit Option"
+
 for further information.
 
 BUGS