File 1812-Implement-socket-support-for-IPPROTO_MPTCP.patch of Package erlang
From edaf963fc0d2e4113529c440eacf452bc31e3f41 Mon Sep 17 00:00:00 2001
From: Raimo Niskanen <raimo@erlang.org>
Date: Fri, 24 Oct 2025 16:19:04 +0200
Subject: [PATCH 2/3] Implement `socket` support for IPPROTO_MPTCP
---
erts/emulator/nifs/common/prim_socket_nif.c | 20 ++++++++++++++++++--
erts/emulator/nifs/common/socket_int.h | 1 +
lib/kernel/src/socket.erl | 12 ++++++++----
3 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/erts/emulator/nifs/common/prim_socket_nif.c b/erts/emulator/nifs/common/prim_socket_nif.c
index 654b44ef7a..05d44d1343 100644
--- a/erts/emulator/nifs/common/prim_socket_nif.c
+++ b/erts/emulator/nifs/common/prim_socket_nif.c
@@ -2147,6 +2147,7 @@ static const struct in6_addr in6addr_loopback =
GLOBAL_ATOM_DECL(min_rtt); \
GLOBAL_ATOM_DECL(monitor); \
GLOBAL_ATOM_DECL(more); \
+ GLOBAL_ATOM_DECL(mptcp); \
GLOBAL_ATOM_DECL(msfilter); \
GLOBAL_ATOM_DECL(mss); \
GLOBAL_ATOM_DECL(mtu); \
@@ -4904,6 +4905,13 @@ ERL_NIF_TERM esock_supports_protocols(ErlNifEnv* env)
MKT2(env, MKL1(env, esock_atom_igmp), MKI(env, IPPROTO_IGMP)),
protocols);
+#ifdef IPPROTO_MPTCP
+ protocols =
+ MKC(env,
+ MKT2(env, MKL1(env, esock_atom_mptcp), MKI(env, IPPROTO_MPTCP)),
+ protocols);
+#endif
+
return protocols;
}
@@ -12100,7 +12108,11 @@ void esock_dec_socket(int domain, int type, int protocol)
/* *** Protocol counter *** */
if (protocol == IPPROTO_IP)
esock_cnt_dec(&data.numProtoIP, 1);
- else if (protocol == IPPROTO_TCP)
+ else if (protocol == IPPROTO_TCP
+#ifdef IPPROTO_MPTCP
+ || protocol == IPPROTO_MPTCP
+#endif
+ )
esock_cnt_dec(&data.numProtoTCP, 1);
else if (protocol == IPPROTO_UDP)
esock_cnt_dec(&data.numProtoUDP, 1);
@@ -12145,7 +12157,11 @@ void esock_inc_socket(int domain, int type, int protocol)
/* *** Protocol counter *** */
if (protocol == IPPROTO_IP)
esock_cnt_inc(&data.numProtoIP, 1);
- else if (protocol == IPPROTO_TCP)
+ else if (protocol == IPPROTO_TCP
+#ifdef IPPROTO_MPTCP
+ || protocol == IPPROTO_MPTCP
+#endif
+ )
esock_cnt_inc(&data.numProtoTCP, 1);
else if (protocol == IPPROTO_UDP)
esock_cnt_inc(&data.numProtoUDP, 1);
diff --git a/erts/emulator/nifs/common/socket_int.h b/erts/emulator/nifs/common/socket_int.h
index 08dea79fe9..0c20aa86e2 100644
--- a/erts/emulator/nifs/common/socket_int.h
+++ b/erts/emulator/nifs/common/socket_int.h
@@ -425,6 +425,7 @@ typedef long ssize_t;
GLOBAL_ATOM_DEF(min_rtt); \
GLOBAL_ATOM_DEF(monitor); \
GLOBAL_ATOM_DEF(more); \
+ GLOBAL_ATOM_DEF(mptcp); \
GLOBAL_ATOM_DEF(msfilter); \
GLOBAL_ATOM_DEF(mss); \
GLOBAL_ATOM_DEF(mtu); \
diff --git a/lib/kernel/src/socket.erl b/lib/kernel/src/socket.erl
index 690087e3b3..839bec289a 100644
--- a/lib/kernel/src/socket.erl
+++ b/lib/kernel/src/socket.erl
@@ -492,6 +492,9 @@ They have the following names in the OS header files:
- **`tcp`** - `IPPROTO_TCP` with options named `TCP_`\*.
+- **`mptcp`** - `IPPROTO_MPTCP` with a few options named `MPTCP_`\*.
+ Most `TCP_`\* options apply which is the purpose of Multi-Path TCP.
+
- **`udp`** - `IPPROTO_UDP` with options named `UDP_`\*.
- **`sctp`** - `IPPROTO_SCTP` with options named `SCTP_`\*.
@@ -504,10 +507,11 @@ through the `C` library call `getprotoent()`. See the OS man page for
protocols(5). Those in the list above are valid if supported by the platform,
even if they aren't enumerated.
-The calls [`is_supported(ipv6)` ](`is_supported/1`)
-and [`is_supported(sctp)` ](`is_supported/1`) can be used to find out
-if the protocols `ipv6` and `sctp` are supported on the platform
-as in appropriate header file and library exists.
+The calls [`is_supported(ipv6)` ](`is_supported/1`),
+[`is_supported(sctp)` ](`is_supported/1`) and
+[`is_supported(mptcp)` ](`is_supported/1`) can be used to find out
+if the protocols `ipv6`, `sctp` and `mptcp` are supported on the platform
+as in; appropriate header file and libraries exist.
The call [`is_supported(protocols, Protocol)` ](`is_supported/2`)
can only be used to find out if the platform knows the protocol number
--
2.51.0
