socket module add SO_ATTACH_REUSEPORT_CPBF for Linux.

to be used in conjunction with SO_REUSPORT, giving a greater control
over how we bind a socket instead of the round robin workflow, we do
 instead attach to the processor id as :
- we assign the processor_id to A in the BPF filter.
- then returns A.

in other words, a more modern version of SO_INCOMING_CPU (ie can have a per
 worker notion we do not use here).

Author: devnexen

ext/sockets/config.m4

@@ -5,7 +5,7 @@ PHP_ARG_ENABLE([sockets],
 
 if test "$PHP_SOCKETS" != "no"; then
   AC_CHECK_FUNCS([hstrerror if_nametoindex if_indextoname])
-  AC_CHECK_HEADERS([netinet/tcp.h sys/un.h sys/sockio.h])
+  AC_CHECK_HEADERS([netinet/tcp.h sys/un.h sys/sockio.h linux/filter.h])
   AC_DEFINE([HAVE_SOCKETS], 1, [ ])
 
   dnl Check for fied ss_family in sockaddr_storage (missing in AIX until 5.3)

ext/sockets/sockets.c

@@ -55,6 +55,9 @@
 # if HAVE_IF_NAMETOINDEX
 #  include <net/if.h>
 # endif
+# if HAVE_LINUX_FILTER_H
+#  include <linux/filter.h>
+# endif
 #endif
 
 #include <stddef.h>
@@ -506,6 +509,9 @@ static PHP_MINIT_FUNCTION(sockets)
 	REGISTER_LONG_CONSTANT("SO_REUSEADDR",	SO_REUSEADDR,	CONST_CS | CONST_PERSISTENT);
 #ifdef SO_REUSEPORT
 	REGISTER_LONG_CONSTANT("SO_REUSEPORT",	SO_REUSEPORT,	CONST_CS | CONST_PERSISTENT);
+#endif
+#ifdef SO_ATTACH_REUSEPORT_CBPF
+	REGISTER_LONG_CONSTANT("SO_ATTACH_REUSEPORT_CBPF", SO_ATTACH_REUSEPORT_CBPF, CONST_CS | CONST_PERSISTENT);
 #endif
 	REGISTER_LONG_CONSTANT("SO_KEEPALIVE",	SO_KEEPALIVE,	CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("SO_DONTROUTE",	SO_DONTROUTE,	CONST_CS | CONST_PERSISTENT);
@@ -1850,6 +1856,7 @@ PHP_FUNCTION(socket_get_option)
 				return;
 			}
 #endif
+
 		}
 	}
 
@@ -2004,6 +2011,26 @@ PHP_FUNCTION(socket_set_option)
 		}
 #endif
 
+#ifdef SO_ATTACH_REUSEPORT_CBPF
+		case SO_ATTACH_REUSEPORT_CBPF: {
+			convert_to_long(arg4);
+			if (!Z_LVAL_P(arg4)) {
+				RETURN_FALSE;
+			}
+			static struct sock_filter cbpf[] = {
+				BPF_STMT((BPF_LD|BPF_W|BPF_ABS), (uint32_t)(SKF_AD_OFF+SKF_AD_CPU)),
+				BPF_STMT((BPF_RET|BPF_A), 0),
+			};
+			static struct sock_fprog bpfprog = {
+				.len = (sizeof(cbpf) / sizeof(cbpf[0])),
+				.filter = cbpf,
+			};
+			optlen = sizeof(bpfprog);
+			opt_ptr = &bpfprog;
+			break;
+		}
+#endif
+
 		default:
 default_case:
 			convert_to_long(arg4);

ext/sockets/tests/socket_reuseport_cbpf.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Test if socket_set_option() works, option:SO_ATTACH_REUSEPORT_CBPF
+--EXTENSIONS--
+sockets
+--SKIPIF--
+<?php
+
+if (!defined("SO_ATTACH_REUSEPORT_CBPF")) {
+	die('SKIP on platforms not supporting SO_ATTACH_REUSEPORT_CBPF');
+}
+?>
+--FILE--
+<?php
+$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
+
+if (!$socket) {
+        die('Unable to create AF_INET socket [socket]');
+}
+var_dump(socket_set_option( $socket, SOL_SOCKET, SO_REUSEADDR, true));
+var_dump(socket_set_option( $socket, SOL_SOCKET, SO_REUSEPORT, true));
+var_dump(socket_set_option( $socket, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, true));
+var_dump(socket_bind($socket, '0.0.0.0'));
+socket_listen($socket);
+socket_close($socket);
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)