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Merged
nlattice merged 1 commit into from
Aug 12, 2026
Merged

feat(wish/cpp): make it able to set a limit on the max number of conn… #81

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13 changes: 12 additions & 1 deletion wish/cpp/src/h2_server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -96,9 +96,16 @@ void H2Server::AcceptConnCb(evconnlistener* listener,
int /*socklen*/,
void* ctx) {
H2Server* server = static_cast<H2Server*>(ctx);

event_base* base = evconnlistener_get_base(listener);

if (server->max_connections_ > 0 && server->active_sessions_count_ >= server->max_connections_) {
VLOG(1) << "H2Server: Max connections limit reached (" << server->max_connections_ << "). Rejecting connection.";

evutil_closesocket(fd);

return;
}

int one = 1;
int set_rv = setsockopt(fd,
IPPROTO_TCP,
Expand Down Expand Up @@ -145,6 +152,7 @@ void H2Server::AcceptConnCb(evconnlistener* listener,

return;
}
server->active_sessions_count_++;

// Send server connection preface (SETTINGS frame).
nghttp2_settings_entry iv[] = {
Expand Down Expand Up @@ -224,6 +232,9 @@ void H2Server::HandleSessionError(Session* sess) {
if (!sess) {
return;
}
if (sess->server && sess->server->active_sessions_count_ > 0) {
sess->server->active_sessions_count_--;
}
for (auto& [sid, info] : sess->incoming_streams) {
if (info.web_stream) {
info.web_stream->OnError();
Expand Down
7 changes: 7 additions & 0 deletions wish/cpp/src/h2_server.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,8 @@

#include "nghttp2_web_stream.h"

constexpr size_t kDefaultMaxH2Connections = 10000;

// H2Server listens for plain (cleartext) HTTP/2 (h2c) connections and
// exposes each incoming web-stream stream to the caller.
class H2Server {
Expand All @@ -43,6 +45,8 @@ class H2Server {
bool Init();
int GetPort() const;
void SetOnStream(StreamCallback cb);
void SetMaxConnections(size_t max_connections) { max_connections_ = max_connections; }
size_t active_connections() const { return active_sessions_count_; }
int Run();

private:
Expand Down Expand Up @@ -129,6 +133,9 @@ class H2Server {
evconnlistener* listener_;

StreamCallback on_stream_;

size_t max_connections_ = kDefaultMaxH2Connections;
size_t active_sessions_count_ = 0;
};

#endif // WISH_CPP_SRC_H2_SERVER_H_
28 changes: 28 additions & 0 deletions wish/cpp/src/h2_server_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -70,3 +70,31 @@ TEST_F(H2ServerTest, InvalidConnectionPrefaceCleanlyDeallocatesSession) {
close(client_fd);
event_base_loop(base_, EVLOOP_NONBLOCK);
}

TEST_F(H2ServerTest, MaxConnectionsLimitRejectsExtraConnections) {
H2Server server(base_, 0);
server.SetMaxConnections(1);
ASSERT_TRUE(server.Init());

sockaddr_in addr{};
addr.sin_family = AF_INET;
addr.sin_port = htons(server.GetPort());
inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);

// Connection 1
int fd1 = socket(AF_INET, SOCK_STREAM, 0);
ASSERT_GE(fd1, 0);
ASSERT_EQ(connect(fd1, reinterpret_cast<sockaddr*>(&addr), sizeof(addr)), 0);
event_base_loop(base_, EVLOOP_NONBLOCK);
EXPECT_EQ(server.active_connections(), 1u);

// Connection 2 (Should be rejected)
int fd2 = socket(AF_INET, SOCK_STREAM, 0);
ASSERT_GE(fd2, 0);
ASSERT_EQ(connect(fd2, reinterpret_cast<sockaddr*>(&addr), sizeof(addr)), 0);
event_base_loop(base_, EVLOOP_NONBLOCK);
EXPECT_EQ(server.active_connections(), 1u);

close(fd1);
close(fd2);
}
13 changes: 12 additions & 1 deletion wish/cpp/src/h2_tls_server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -119,9 +119,16 @@ void H2TlsServer::AcceptConnCb(evconnlistener* listener,
int /*socklen*/,
void* ctx) {
H2TlsServer* server = static_cast<H2TlsServer*>(ctx);

event_base* base = evconnlistener_get_base(listener);

if (server->max_connections_ > 0 && server->active_sessions_count_ >= server->max_connections_) {
VLOG(1) << "H2TlsServer: Max connections limit reached (" << server->max_connections_ << "). Rejecting connection.";

evutil_closesocket(fd);

return;
}

int one = 1;
int set_rv = setsockopt(fd,
IPPROTO_TCP,
Expand Down Expand Up @@ -175,6 +182,7 @@ void H2TlsServer::AcceptConnCb(evconnlistener* listener,

return;
}
server->active_sessions_count_++;

nghttp2_settings_entry iv[] = {
{NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 100},
Expand Down Expand Up @@ -252,6 +260,9 @@ void H2TlsServer::HandleSessionError(Session* sess) {
if (!sess) {
return;
}
if (sess->server && sess->server->active_sessions_count_ > 0) {
sess->server->active_sessions_count_--;
}
for (auto& [sid, info] : sess->incoming_streams) {
if (info.web_stream) {
info.web_stream->OnError();
Expand Down
7 changes: 7 additions & 0 deletions wish/cpp/src/h2_tls_server.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@
// H2TlsServer listens for TLS-encrypted HTTP/2 connections.
// ALPN "h2" is advertised so standard HTTP/2 clients can connect.
// mTLS is enforced (client certificates are required), matching TlsServer.
constexpr size_t kDefaultMaxH2TlsConnections = 10000;

class H2TlsServer {
public:
using StreamCallback = std::function<void(WebStream*)>;
Expand All @@ -45,6 +47,8 @@ class H2TlsServer {

bool Init();
void SetOnStream(StreamCallback cb);
void SetMaxConnections(size_t max_connections) { max_connections_ = max_connections; }
size_t active_connections() const { return active_sessions_count_; }
int Run();

private:
Expand Down Expand Up @@ -133,6 +137,9 @@ class H2TlsServer {
TlsContext tls_ctx_;

StreamCallback on_stream_;

size_t max_connections_ = kDefaultMaxH2TlsConnections;
size_t active_sessions_count_ = 0;
};

#endif // WISH_CPP_SRC_H2_TLS_SERVER_H_
9 changes: 9 additions & 0 deletions wish/cpp/src/plain_server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,15 @@ void PlainServer::AcceptConnCb(evconnlistener* listener,
event_base* base = evconnlistener_get_base(listener);
PlainServer* server = static_cast<PlainServer*>(ctx);

if (server->max_connections_ > 0 &&
(server->active_handshakes_.size() + server->active_streams_.size()) >= server->max_connections_) {
VLOG(1) << "Max connections limit reached (" << server->max_connections_ << "). Rejecting connection.";

evutil_closesocket(fd);

return;
}

int one = 1;
int set_opt_rv = setsockopt(fd,
IPPROTO_TCP,
Expand Down
6 changes: 6 additions & 0 deletions wish/cpp/src/plain_server.h
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,8 @@
class ServerHandshake;
class BufferEventWebStream;

constexpr size_t kDefaultMaxConnections = 10000;

class PlainServer {
public:
using StreamCallback = std::function<void(WebStream*)>;
Expand All @@ -40,6 +42,8 @@ class PlainServer {

bool Init();
void SetOnStream(StreamCallback cb);
void SetMaxConnections(size_t max_connections) { max_connections_ = max_connections; }
size_t active_connections() const { return active_handshakes_.size() + active_streams_.size(); }
int Run();

private:
Expand All @@ -62,6 +66,8 @@ class PlainServer {

StreamCallback on_stream_;

size_t max_connections_ = kDefaultMaxConnections;

std::vector<std::unique_ptr<ServerHandshake>> active_handshakes_;
std::vector<std::unique_ptr<BufferEventWebStream>> active_streams_;
};
Expand Down
9 changes: 9 additions & 0 deletions wish/cpp/src/tls_server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -110,6 +110,15 @@ void TlsServer::AcceptConnCb(evconnlistener* listener,
event_base* base = evconnlistener_get_base(listener);
TlsServer* server = static_cast<TlsServer*>(ctx);

if (server->max_connections_ > 0 &&
(server->active_handshakes_.size() + server->active_streams_.size()) >= server->max_connections_) {
VLOG(1) << "Max TLS connections limit reached (" << server->max_connections_ << "). Rejecting connection.";

evutil_closesocket(fd);

return;
}

int one = 1;
int set_opt_rv = setsockopt(fd,
IPPROTO_TCP,
Expand Down
6 changes: 6 additions & 0 deletions wish/cpp/src/tls_server.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@
class ServerHandshake;
class BufferEventWebStream;

constexpr size_t kDefaultMaxTlsConnections = 10000;

class TlsServer {
public:
using StreamCallback = std::function<void(WebStream*)>;
Expand All @@ -45,6 +47,8 @@ class TlsServer {

bool Init();
void SetOnStream(StreamCallback cb);
void SetMaxConnections(size_t max_connections) { max_connections_ = max_connections; }
size_t active_connections() const { return active_handshakes_.size() + active_streams_.size(); }
int Run();

private:
Expand Down Expand Up @@ -73,6 +77,8 @@ class TlsServer {

StreamCallback on_stream_;

size_t max_connections_ = kDefaultMaxTlsConnections;

std::vector<std::unique_ptr<ServerHandshake>> active_handshakes_;
std::vector<std::unique_ptr<BufferEventWebStream>> active_streams_;
};
Expand Down