[core] Detect reusable bindings and binding conflicts correctly (#1588).

Introduced new SRT socket error SRT_EBINDCONFLICT.
Haivision · May 28, 2021 · e2a00aa · e2a00aa
1 parent 44eb6ce
commit e2a00aa
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Showing 10 changed files with 672 additions and 90 deletions.
diff --git a/.travis.yml b/.travis.yml
@@ -58,7 +58,7 @@ matrix:
             - make
             - cd ..
           env: BUILD_TYPE=Release
-          
+
          # Power jobs
         - os: linux
           arch: ppc64le
@@ -69,6 +69,7 @@ matrix:
           - BUILD_TYPE=Release
           - BUILD_OPTS='-DENABLE_MONOTONIC_CLOCK=ON'
 script:
+    - TESTS_IPv6="TestMuxer.IPv4_and_IPv6:TestIPv6.v6_calls_v6*:ReuseAddr.ProtocolVersion" ; # Tests to skip due to lack of IPv6 support
     - if [ "$TRAVIS_COMPILER" == "x86_64-w64-mingw32-g++" ]; then
         export CC="x86_64-w64-mingw32-gcc";
         export CXX="x86_64-w64-mingw32-g++";
@@ -91,7 +92,7 @@ script:
         make -j$(nproc);
       fi
     - if [ "$TRAVIS_COMPILER" != "x86_64-w64-mingw32-g++" ]; then
-        ./test-srt --gtest_filter="-TestMuxer.IPv4_and_IPv6:TestIPv6.v6_calls_v6*";
+        ./test-srt --gtest_filter="-$TESTS_IPv6";
       fi
     - if (( "$RUN_CODECOV" )); then
         source ./scripts/collect-gcov.sh;

diff --git a/docs/API/API-functions.md b/docs/API/API-functions.md
@@ -384,13 +384,14 @@ connecting, use [`srt_connect_bind`](#srt_connect_bind) for that purpose.
 | `SRT_ERROR`                   | (-1) on error, otherwise 0                                |
 | <img width=240px height=1px/> | <img width=710px height=1px/>                      |
 
-|       Errors                        |                                                                      |
-|:----------------------------------- |:-------------------------------------------------------------------- |
-| [`SRT_EINVSOCK`](#srt_einvsock)     | Socket passed as [`u`](#u) designates no valid socket                |
-| [`SRT_EINVOP`](#srt_einvop)         | Socket already bound                                                 |
-| [`SRT_ECONNSETUP`](#srt_econnsetup) | Internal creation of a UDP socket failed                             |
-| [`SRT_ESOCKFAIL`](#srt_esockfail)   | Internal configuration of a UDP socket (`bind`, `setsockopt`) failed |
-| <img width=240px height=1px/>       | <img width=710px height=1px/>                      |
+|       Errors                             |                                                                      |
+|:---------------------------------------- |:-------------------------------------------------------------------- |
+| [`SRT_EINVSOCK`](#srt_einvsock)          | Socket passed as [`u`](#u) designates no valid socket                |
+| [`SRT_EINVOP`](#srt_einvop)              | Socket already bound                                                 |
+| [`SRT_ECONNSETUP`](#srt_econnsetup)      | Internal creation of a UDP socket failed                             |
+| [`SRT_ESOCKFAIL`](#srt_esockfail)        | Internal configuration of a UDP socket (`bind`, `setsockopt`) failed |
+| [`SRT_EBINDCONFLICT`](#srt_ebindconflict)| Binding specification conflicts with existing one                    |
+| <img width=240px height=1px/>            | <img width=710px height=1px/>                                        |
 
 
 [:arrow_up: &nbsp; Back to List of Functions & Structures](#srt-api-functions)
@@ -841,18 +842,19 @@ first on the automatically created socket for the connection.
 |    `SRT_ERROR`                | (-1) in case of error                                    |
 |         0                     | In case when used for [`u`](#u) socket                   |
 |    Socket ID                  | Created for connection for [`u`](#u) group               |
-| <img width=240px height=1px/> | <img width=710px height=1px/>                      |
+| <img width=240px height=1px/> | <img width=710px height=1px/>                            |
 
-|       Errors                          |                                                          |
-|:------------------------------------- |:-------------------------------------------------------- |
-| [`SRT_EINVSOCK`](#srt_einvsock)       | Socket passed as [`u`](#u) designates no valid socket    |
-| [`SRT_EINVOP`](#srt_einvop)           | Socket already bound                                     |
-| [`SRT_ECONNSETUP`](#srt_econnsetup)   | Internal creation of a UDP socket failed                 |
-| [`SRT_ESOCKFAIL`](#srt_esockfail)     | Internal configuration of a UDP socket (`bind`, `setsockopt`) failed   |
-| [`SRT_ERDVUNBOUND`](#srt_erdvunbound) | Internal error ([`srt_connect`](#srt_connect) should not report it after [`srt_bind`](#srt_bind) was called)   |
-| [`SRT_ECONNSOCK`](#srt_econnsock)     | Socket [`u`](#u) is already connected                    |
-| [`SRT_ECONNREJ`](#srt_econnrej)       | Connection has been rejected                             |
-| <img width=240px height=1px/>         | <img width=710px height=1px/>                      |
+|       Errors                             |                                                          |
+|:---------------------------------------- |:-------------------------------------------------------- |
+| [`SRT_EINVSOCK`](#srt_einvsock)          | Socket passed as [`u`](#u) designates no valid socket    |
+| [`SRT_EINVOP`](#srt_einvop)              | Socket already bound                                     |
+| [`SRT_ECONNSETUP`](#srt_econnsetup)      | Internal creation of a UDP socket failed                 |
+| [`SRT_ESOCKFAIL`](#srt_esockfail)        | Internal configuration of a UDP socket (`bind`, `setsockopt`) failed   |
+| [`SRT_ERDVUNBOUND`](#srt_erdvunbound)    | Internal error ([`srt_connect`](#srt_connect) should not report it after [`srt_bind`](#srt_bind) was called)   |
+| [`SRT_ECONNSOCK`](#srt_econnsock)        | Socket [`u`](#u) is already connected                    |
+| [`SRT_ECONNREJ`](#srt_econnrej)          | Connection has been rejected                             |
+| [`SRT_EBINDCONFLICT`](#srt_ebindconflict)| Binding specification conflicts with existing one        |
+| <img width=240px height=1px/>            | <img width=710px height=1px/>                            |
 
 
 **IMPORTANT**: It's not allowed to bind and connect the same socket to two
@@ -3225,6 +3227,54 @@ by setting the `SRT_EPOLL_ENABLE_EMPTY` flag, which may be useful when
 you use multiple threads and start waiting without subscribed sockets, so that
 you can subscribe them later from another thread.
 
+
+#### `SRT_EBINDCONFLICT`
+
+The binding you are attempting to set up a socket with cannot be completed because
+it conflicts with another existing binding. This is because an intersecting binding
+was found that cannot be reused according to the specification in `srt_bind` call.
+
+A binding is considered intersecting if the existing binding has the same port
+and covers at least partially the range as that of the attempted binding. These
+ranges can be split in three groups:
+
+1. An explicitly specified IP address (both IPv4 and IPv6) covers this address only.
+2. An IPv4 wildcard 0.0.0.0 covers all IPv4 addresses (but not IPv6).
+3. An IPv6 wildcard :: covers:
+   * if `SRTO_IPV6ONLY` is true - all IPv6 addresses (but not IPv4)
+   * if `SRTO_IPV6ONLY` is false - all IP addresses.
+
+Example 1:
+
+* Socket 1: bind to IPv4 0.0.0.0
+* Socket 2: bind to IPv6 :: with `SRTO_IPV6ONLY` = true
+* Result: NOT intersecting
+
+Example 2:
+
+* Socket 1: bind to IPv4 1.2.3.4
+* Socket 2: bind to IPv4 0.0.0.0
+* Result: intersecting (and conflicting)
+
+Example 3:
+
+* Socket 1: bind to IPv4 1.2.3.4
+* Socket 2: bind to IPv6 :: with `SRTO_IPV6ONLY` = false
+* Result: intersecting (and conflicting)
+
+If any common range coverage is found between the attempted binding specification
+(in `srt_bind` call) and the found existing binding with the same port number,
+then all of the following conditions must be satisfied between them:
+
+1. The `SRTO_REUSEADDR` must be true (default) in both.
+
+2. The IP address specification (in case of IPv6, also including the value of
+`SRTO_IPV6ONLY` flag) must be exactly identical.
+
+3. The UDP-specific settings must be identical.
+
+If any of these conditions isn't satisfied, the `srt_bind` function results
+in conflict and report this error.
 
 #### SRT_EASYNCFAIL
 

diff --git a/scripts/generate-error-types.tcl b/scripts/generate-error-types.tcl
@@ -61,6 +61,7 @@ set code_minor {
     XSIZE           12
     EIDINVAL        13
     EEMPTY          14
+    BUSYPORT        15
 
     WRAVAIL          1
     RDAVAIL          2
@@ -121,7 +122,7 @@ set errortypes {
         XSIZE          "Message is too large to send (it must be less than the SRT send buffer size)"
         EIDINVAL       "Invalid epoll ID"
         EEMPTY         "All sockets removed from epoll, waiting would deadlock"
-
+        BUSYPORT       "Another socket is bound to that port and is not reusable for requested settings"
     }
 
     AGAIN "Non-blocking call failure" {
@@ -142,11 +143,10 @@ set main_array_item {
 const char** strerror_array_major [] = {
 $minor_array_list
 };
-
 }
 
 set major_size_item {
-size_t strerror_array_sizes [] = {
+const size_t strerror_array_sizes [] = {
 $minor_array_sizes
 };
 }
@@ -155,11 +155,9 @@ set minor_array_item {
 const char* strerror_msgs_$majorlc [] = {
 $minor_message_items
 };
-
 }
 
 set strerror_function {
-
 const char* strerror_get_message(size_t major, size_t minor)
 {
     static const char* const undefined = "UNDEFINED ERROR";
@@ -228,16 +226,17 @@ proc Generate:imp {} {
         puts [subst -nobackslashes -nocommands $::minor_array_item]
 
         append minor_array_list "    strerror_msgs_$majorlc, // MJ_$mt = $majitem\n"
-        append minor_array_sizes "    [expr {$minitem}],\n"
+        #append minor_array_sizes "    [expr {$minitem}],\n"
+        append minor_array_sizes "    SRT_ARRAY_SIZE(strerror_msgs_$majorlc) - 1,\n"
         incr majitem
     }
-    append minor_array_list "    NULL\n"
-    append minor_array_sizes "    0\n"
+    append minor_array_list "    NULL"
+    append minor_array_sizes "    0"
 
     puts [subst -nobackslashes -nocommands $::main_array_item]
+    puts {#define SRT_ARRAY_SIZE(ARR) sizeof(ARR) / sizeof(ARR[0])}
     puts [subst -nobackslashes -nocommands $::major_size_item]
 
-    puts ""
     puts $::strerror_function
 
     puts "\} // namespace srt"
@@ -250,4 +249,3 @@ if {[lindex $argv 0] != ""} {
 }
 
 Generate:$defmode
-