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).
Closes #8062

Author: devnexen

NEWS

@@ -2,6 +2,10 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.3.0alpha1
 
+- CLI:
+  . Added pdeathsig to builtin server to terminate workers when the master
+    process is killed. (ilutov)
+
 - Core:
   . Fixed bug GH-9388 (Improve unset property and __get type incompatibility
     error message). (ilutov)
@@ -17,9 +21,8 @@ PHP                                                                        NEWS
 - Posix:
   . Added posix_sysconf. (David Carlier)
 
-- CLI:
-  . Added pdeathsig to builtin server to terminate workers when the master
-    process is killed. (ilutov)
-
+- Sockets:
+  . Added SO_ATTACH_REUSEPORT_CBPF socket option, to give tighter control
+  over socket binding for a cpu core. (David Carlier)
 
 <<< NOTE: Insert NEWS from last stable release here prior to actual release! >>>

UPGRADING

@@ -64,6 +64,9 @@ PHP 8.3 UPGRADE NOTES
   . POSIX_SC_NPROCESSORS_CONF
   . POSIX_SC_NPROCESSORS_ONLN
 
+- Sockets:
+  . SO_ATTACH_REUSEPORT_CBPF (Linux only).
+
 ========================================
 11. Changes to INI File Handling
 ========================================

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

@@ -1741,6 +1741,7 @@ PHP_FUNCTION(socket_get_option)
 				return;
 			}
 #endif
+
 		}
 	}
 
@@ -1960,6 +1961,40 @@ 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)) {
+				ov = 1;
+				optlen = sizeof(ov);
+				opt_ptr = &ov;
+				optname = SO_DETACH_BPF;
+			} else {
+				uint32_t k = (uint32_t)Z_LVAL_P(arg4);
+				static struct sock_filter cbpf[8] = {0};
+				static struct sock_fprog bpfprog;
+
+				switch (k) {
+                		case SKF_AD_CPU:
+					cbpf[0].code = (BPF_LD|BPF_W|BPF_ABS);
+                    			cbpf[0].k = (uint32_t)(SKF_AD_OFF + k);
+					cbpf[1].code = (BPF_RET|BPF_A);
+                    			bpfprog.len = 2;
+                    		break;
+                		default:
+                    			php_error_docref(NULL, E_WARNING, "Unsupported CBPF filter");
+                    			RETURN_FALSE;
+                		}
+
+				bpfprog.filter = cbpf;
+				optlen = sizeof(bpfprog);
+				opt_ptr = &bpfprog;
+			}
+			break;
+		}
+#endif
+
 		default:
 default_case:
 			convert_to_long(arg4);

ext/sockets/sockets.stub.php

@@ -1678,6 +1678,27 @@
  */
 const LOCAL_CREDS = UNKNOWN;
 #endif
+#if defined(SO_ATTACH_REUSEPORT_CBPF)
+/**
+ * @var int
+ * @cvalue SO_ATTACH_REUSEPORT_CBPF
+ */
+const SO_ATTACH_REUSEPORT_CBPF = UNKNOWN;
+#endif
+#if defined(SO_DETACH_FILTER)
+/**
+ * @var int
+ * @cvalue SO_DETACH_FILTER
+ */
+const SO_DETACH_FILTER = UNKNOWN;
+#endif
+#if defined(SO_DETACH_BPF)
+/**
+ * @var int
+ * @cvalue SO_DETACH_BPF
+ */
+const SO_DETACH_BPF = UNKNOWN;
+#endif
 
 /**
  * @strict-properties

ext/sockets/sockets_arginfo.h

@@ -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( $socket, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, SKF_AD_CPU));
+var_dump(socket_bind($socket, '0.0.0.0'));
+socket_listen($socket);
+socket_close($socket);
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)