From cb5329b2cada0827c9b810eeedeb96cfc6011149 Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@gmail.com>
Date: Tue, 16 Jul 2024 20:58:42 -0400
Subject: [PATCH] simplify poll implementation;

---
 src/common/network/tcp/Socket.cpp | 64 ++++++++-----------------------
 src/common/network/tcp/Socket.h   |  4 --
 src/common/network/udp/Socket.cpp | 36 +++++------------
 src/common/network/udp/Socket.h   |  4 --
 4 files changed, 26 insertions(+), 82 deletions(-)

diff --git a/src/common/network/tcp/Socket.cpp b/src/common/network/tcp/Socket.cpp
index 1ccaa28d..06a8f60e 100644
--- a/src/common/network/tcp/Socket.cpp
+++ b/src/common/network/tcp/Socket.cpp
@@ -65,38 +65,22 @@ Socket::~Socket()
 int Socket::accept(sockaddr* address, socklen_t* addrlen) noexcept
 {
     // check that the accept() won't block
-    int i, n;
-    struct pollfd pfd[TCP_SOCKET_MAX];
-    for (i = n = 0; i < TCP_SOCKET_MAX; i++) {
-        if (m_fd >= 0) {
-            pfd[n].fd = m_fd;
-            pfd[n].events = POLLIN;
-            n++;
-        }
-    }
-
-    // no socket descriptor to receive
-    if (n == 0)
-        return 0;
+    struct pollfd pfd;
+    pfd.fd = m_fd;
+    pfd.events = POLLIN;
+    pfd.revents = 0;
 
-    // Return immediately
-    int ret = ::poll(pfd, n, 0);
+    // return immediately
+    int ret = ::poll(&pfd, 1, 0);
     if (ret < 0) {
         LogError(LOG_NET, "Error returned from TCP poll, err: %d", errno);
         return -1;
     }
 
-    int index;
-    for (i = 0; i < n; i++) {
-        // round robin
-        index = (i + m_counter) % n;
-        if (pfd[index].revents & POLLIN)
-            break;
-    }
-    if (i == n)
+    if ((pfd.revents & POLLIN) == 0)
         return -1;
 
-    return ::accept(pfd[index].fd, address, addrlen);
+    return ::accept(pfd.fd, address, addrlen);
 }
 
 /* Connects the client to a remote TCP host using the specified host name and port number. */
@@ -143,39 +127,23 @@ ssize_t Socket::listen(const std::string& ipAddr, const uint16_t port, int backl
         return -1;
 
     // check that the read() won't block
-    int i, n;
-    struct pollfd pfd[TCP_SOCKET_MAX];
-    for (i = n = 0; i < TCP_SOCKET_MAX; i++) {
-        if (m_fd >= 0) {
-            pfd[n].fd = m_fd;
-            pfd[n].events = POLLIN;
-            n++;
-        }
-    }
-
-    // no socket descriptor to receive
-    if (n == 0)
-        return 0;
+    struct pollfd pfd;
+    pfd.fd = m_fd;
+    pfd.events = POLLIN;
+    pfd.revents = 0;
 
-    // Return immediately
-    int ret = ::poll(pfd, n, 0);
+    // return immediately
+    int ret = ::poll(&pfd, 1, 0);
     if (ret < 0) {
         LogError(LOG_NET, "Error returned from TCP poll, err: %d", errno);
         return -1;
     }
 
-    int index;
-    for (i = 0; i < n; i++) {
-        // round robin
-        index = (i + m_counter) % n;
-        if (pfd[index].revents & POLLIN)
-            break;
-    }
-    if (i == n)
+    if ((pfd.revents & POLLIN) == 0)
         return 0;
 
     m_counter++;
-    return ::read(pfd[index].fd, (char*)buffer, length);
+    return ::read(pfd.fd, (char*)buffer, length);
 }
 
 /* Write data to the socket. */
diff --git a/src/common/network/tcp/Socket.h b/src/common/network/tcp/Socket.h
index 75e500bd..de41cf01 100644
--- a/src/common/network/tcp/Socket.h
+++ b/src/common/network/tcp/Socket.h
@@ -33,10 +33,6 @@
 #include <cstdlib>
 #include <ctime>
 
-#if !defined(TCP_SOCKET_MAX)
-#define TCP_SOCKET_MAX	1
-#endif
-
 namespace network
 {
     namespace tcp
diff --git a/src/common/network/udp/Socket.cpp b/src/common/network/udp/Socket.cpp
index 1e9bf6b1..1adfe807 100644
--- a/src/common/network/udp/Socket.cpp
+++ b/src/common/network/udp/Socket.cpp
@@ -149,40 +149,24 @@ ssize_t Socket::read(uint8_t* buffer, uint32_t length, sockaddr_storage& address
     if (m_fd < 0)
         return -1;
 
-    // Check that the readfrom() won't block
-    int i, n;
-    struct pollfd pfd[UDP_SOCKET_MAX];
-    for (i = n = 0; i < UDP_SOCKET_MAX; i++) {
-        if (m_fd >= 0) {
-            pfd[n].fd = m_fd;
-            pfd[n].events = POLLIN;
-            n++;
-        }
-    }
-
-    // no socket descriptor to receive
-    if (n == 0)
-        return 0;
-
-    // Return immediately
-    int ret = ::poll(pfd, n, 0);
+    // check that the readfrom() won't block
+    struct pollfd pfd;
+    pfd.fd = m_fd;
+    pfd.events = POLLIN;
+    pfd.revents = 0;
+
+    // return immediately
+    int ret = ::poll(&pfd, 1, 0);
     if (ret < 0) {
         LogError(LOG_NET, "Error returned from UDP poll, err: %d", errno);
         return -1;
     }
 
-    int index;
-    for (i = 0; i < n; i++) {
-        // round robin
-        index = (i + m_counter) % n;
-        if (pfd[index].revents & POLLIN)
-            break;
-    }
-    if (i == n)
+    if ((pfd.revents & POLLIN) == 0)
         return 0;
 
     socklen_t size = sizeof(sockaddr_storage);
-    ssize_t len = ::recvfrom(pfd[index].fd, (char*)buffer, length, 0, (sockaddr*)& address, &size);
+    ssize_t len = ::recvfrom(pfd.fd, (char*)buffer, length, 0, (sockaddr*)& address, &size);
     if (len <= 0) {
         LogError(LOG_NET, "Error returned from recvfrom, err: %d", errno);
 
diff --git a/src/common/network/udp/Socket.h b/src/common/network/udp/Socket.h
index dbf4f6cf..933ef421 100644
--- a/src/common/network/udp/Socket.h
+++ b/src/common/network/udp/Socket.h
@@ -37,10 +37,6 @@
 #include <arpa/inet.h>
 #include <errno.h>
 
-#if !defined(UDP_SOCKET_MAX)
-#define UDP_SOCKET_MAX	1
-#endif
-
 #define AES_WRAPPED_PCKT_MAGIC 0xC0FEU
 #define AES_WRAPPED_PCKT_KEY_LEN 32