From b4d6df902253637f24647d3db2bc3781d69eec1c Mon Sep 17 00:00:00 2001
From: Joel Klinghed <the_jk@spawned.biz>
Date: Thu, 20 Feb 2025 22:54:56 +0100
Subject: Initial commit

---
 src/net.cc | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 src/net.cc

(limited to 'src/net.cc')

diff --git a/src/net.cc b/src/net.cc
new file mode 100644
index 0000000..bb25e69
--- /dev/null
+++ b/src/net.cc
@@ -0,0 +1,136 @@
+#include "net.hh"
+
+#include <charconv>
+#include <cerrno>
+#include <cstring>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+namespace net {
+
+std::vector<unique_fd> bind_and_listen(
+    Logger* logger, std::string const& host, uint16_t port) {
+  std::vector<unique_fd> fds;
+
+  std::string service;
+  service.resize(10);
+  {
+    auto [ptr, err] = std::to_chars(service.data(),
+                                    service.data() + service.size(), port);
+    if (err != std::errc{}) {
+      logger->err("Invalid port: %u", static_cast<unsigned int>(port));
+      return {};
+    }
+    service.resize(ptr - service.data());
+  }
+
+  struct addrinfo hints;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_ADDRCONFIG;
+  struct addrinfo* result;
+
+  if (auto err = getaddrinfo(host.empty() ? nullptr : host.c_str(),
+                             service.c_str(),
+                             &hints, &result)) {
+    logger->err("Unable to resolve %s:%u: %s",
+                host.c_str(), static_cast<unsigned int>(port),
+                gai_strerror(err));
+    return {};
+  }
+
+  for (auto* rp = result; rp; rp = rp->ai_next) {
+    unique_fd fd(socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol));
+    if (!fd) {
+      logger->warn("Unable to create socket: %s", strerror(errno));
+      continue;
+    }
+
+    if (bind(fd.get(), rp->ai_addr, rp->ai_addrlen)) {
+      logger->warn("Unable to bind socket: %s", strerror(errno));
+      continue;
+    }
+
+    fds.push_back(std::move(fd));
+  }
+
+  freeaddrinfo(result);
+
+  {
+    auto it = fds.begin();
+    while (it != fds.end()) {
+      if (listen(it->get(), SOMAXCONN)) {
+        logger->err("Unable to listen: %s", strerror(errno));
+        it = fds.erase(it);
+      } else {
+        ++it;
+      }
+    }
+  }
+  return fds;
+}
+
+unique_fd connect(Logger* logger, std::string const& host, uint16_t port) {
+  unique_fd fd;
+  std::string service;
+  service.resize(10);
+  {
+    auto [ptr, err] = std::to_chars(service.data(),
+                                    service.data() + service.size(), port);
+    if (err != std::errc{}) {
+      logger->err("Invalid port: %u", static_cast<unsigned int>(port));
+      return fd;
+    }
+    service.resize(ptr - service.data());
+  }
+
+  struct addrinfo hints;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_flags = AI_NUMERICSERV | AI_ADDRCONFIG;
+  struct addrinfo* result;
+
+  if (auto err = getaddrinfo(host.c_str(), service.c_str(),
+                             &hints, &result)) {
+    logger->err("Unable to resolve %s:%u: %s",
+                host.c_str(), static_cast<unsigned int>(port),
+                gai_strerror(err));
+    return fd;
+  }
+
+  for (auto* rp = result; rp; rp = rp->ai_next) {
+    // Note: SOCK_NONBLOCK is a linux 2.6.27+ thing.
+    fd.reset(socket(rp->ai_family, rp->ai_socktype | SOCK_NONBLOCK,
+                    rp->ai_protocol));
+    if (!fd) {
+      logger->warn("Unable to create socket: %s", strerror(errno));
+      continue;
+    }
+
+    if (connect(fd.get(), rp->ai_addr, rp->ai_addrlen)) {
+      logger->warn("Unable to connect socket: %s", strerror(errno));
+      fd.reset();
+      continue;
+    }
+
+    break;
+  }
+
+  freeaddrinfo(result);
+  return fd;
+}
+
+unique_fd accept(Logger* logger, int fd) {
+  unique_fd ret(accept4(fd, nullptr, nullptr, SOCK_NONBLOCK));
+  if (!ret) {
+    if (errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR) {
+      logger->warn("Error accepting connection: %s", strerror(errno));
+    }
+  }
+  return ret;
+}
+
+}  // namespace net
-- 
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