init

1 files changed, 277 insertions, 0 deletions

diff --git a/src/conn.cpp b/src/conn.cpp
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index 0000000..b323340
--- /dev/null
+++ b/src/conn.cpp
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+/**
+ * Copyright (c) 2018 Cornell University.
+ *
+ * Author: Ted Yin <tederminant@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is furnished to do
+ * so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <cstring>
+#include <cassert>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "salticidae/util.h"
+#include "salticidae/conn.h"
+
+namespace salticidae {
+
+ConnPool::Conn::operator std::string() const {
+    return "<Conn fd=" + std::to_string(fd) + " " +
+                "addr=" + std::string(addr).c_str() + " " +
+                "mode=" + ((mode == Conn::ACTIVE) ? "active" : "passive") +
+            ">";
+}
+
+void ConnPool::Conn::send_data(evutil_socket_t fd, short events) {
+    if (!(events & EV_WRITE)) return;
+    auto conn = self(); /* pin the connection */
+    ssize_t ret = BUFF_SEG_SIZE;
+    while (ret == BUFF_SEG_SIZE)
+    {
+        if (!send_buffer.size()) /* nothing to write */
+            break;
+        bytearray_t buff_seg = send_buffer.pop(BUFF_SEG_SIZE);
+        ssize_t size = buff_seg.size();
+        ret = send(fd, buff_seg.data(), size, MSG_NOSIGNAL);
+        SALTICIDAE_LOG_DEBUG("socket sent %d bytes", ret);
+        if (ret < size)
+        {
+            if (ret < 0) /* nothing is sent */
+            {
+                /* rewind the whole buff_seg */
+                send_buffer.push(std::move(buff_seg));
+                if (errno != EWOULDBLOCK)
+                {
+                    SALTICIDAE_LOG_INFO("reason: %s", strerror(errno));
+                    terminate();
+                    return;
+                }
+            }
+            else
+            {
+                /* rewind the leftover */
+                bytearray_t left_over;
+                left_over.resize(size - ret);
+                memmove(left_over.data(), buff_seg.data() + ret, size - ret);
+                send_buffer.push(std::move(left_over));
+            }
+            /* wait for the next write callback */
+            ready_send = false;
+            ev_write.add();
+            return;
+        }
+    }
+    /* consumed the buffer but endpoint still seems to be writable */
+    ready_send = true;
+}
+
+void ConnPool::Conn::recv_data(evutil_socket_t fd, short events) {
+    if (!(events & EV_READ)) return;
+    auto conn = self(); /* pin the connection */
+    ssize_t ret = BUFF_SEG_SIZE;
+    while (ret == BUFF_SEG_SIZE)
+    {
+        bytearray_t buff_seg;
+        buff_seg.resize(BUFF_SEG_SIZE);
+        ret = recv(fd, buff_seg.data(), BUFF_SEG_SIZE, 0);
+        SALTICIDAE_LOG_DEBUG("socket read %d bytes", ret);
+        if (ret <= 0)
+        {
+            if (ret < 0 && errno != EWOULDBLOCK)
+            {
+                SALTICIDAE_LOG_INFO("reason: %s", strerror(errno));
+                /* connection err or half-opened connection */
+                terminate();
+                return;
+            }
+            if (ret == 0)
+            {
+                terminate();
+                return;
+            }
+
+            /* EWOULDBLOCK */
+            break;
+        }
+        buff_seg.resize(ret);
+        recv_buffer.push(std::move(buff_seg));
+    }
+    ev_read.add();
+    on_read();
+}
+
+void ConnPool::accept_client(evutil_socket_t fd, short) {
+    int client_fd;
+    struct sockaddr client_addr;
+    socklen_t addr_size = sizeof(struct sockaddr_in);
+    if ((client_fd = accept(fd, &client_addr, &addr_size)) < 0)
+        SALTICIDAE_LOG_ERROR("error while accepting the connection");
+    else
+    {
+        int one = 1;
+        if (setsockopt(client_fd, SOL_TCP, TCP_NODELAY, (const char *)&one, sizeof(one)) < 0)
+            throw ConnPoolError(std::string("setsockopt failed"));
+        if (fcntl(client_fd, F_SETFL, O_NONBLOCK) == -1)
+            throw ConnPoolError(std::string("unable to set nonblocking socket"));
+
+        NetAddr addr((struct sockaddr_in *)&client_addr);
+        conn_t conn = create_conn();
+        Conn *conn_ptr = conn;
+        conn->fd = client_fd;
+        conn->cpool = this;
+        conn->mode = Conn::PASSIVE;
+        conn->addr = addr;
+        conn->ev_read = Event(eb, client_fd, EV_READ,
+                                std::bind(&Conn::recv_data, conn_ptr, _1, _2));
+        conn->ev_write = Event(eb, client_fd, EV_WRITE,
+                                std::bind(&Conn::send_data, conn_ptr, _1, _2));
+        conn->ev_read.add();
+        conn->ev_write.add();
+        conn->ready_send = false;
+        add_conn(conn);
+        SALTICIDAE_LOG_INFO("created connection %s", std::string(*conn).c_str());
+        conn->on_setup();
+    }
+    ev_listen.add();
+}
+
+void ConnPool::Conn::conn_server(evutil_socket_t fd, short events) {
+    auto conn = self(); /* pin the connection */
+    if (send(fd, "", 0, MSG_NOSIGNAL) == 0)
+    {
+        ev_read = Event(cpool->eb, fd, EV_READ,
+                std::bind(&Conn::recv_data, this, _1, _2));
+        ev_write = Event(cpool->eb, fd, EV_WRITE,
+                std::bind(&Conn::send_data, this, _1, _2));
+        ev_read.add();
+        ev_write.add();
+        ev_connect.clear();
+        ready_send = false;
+        SALTICIDAE_LOG_INFO("connected to peer %s", std::string(*this).c_str());
+        on_setup();
+    }
+    else
+    {
+        if (events & EV_TIMEOUT)
+            SALTICIDAE_LOG_INFO("%s connect timeout", std::string(*this).c_str());
+        terminate();
+        return;
+    }
+}
+
+void ConnPool::init(NetAddr listen_addr) {
+    int one = 1;
+    if ((listen_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
+        throw ConnPoolError(std::string("cannot create socket for listening"));
+    if (setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&one, sizeof(one)) < 0 ||
+        setsockopt(listen_fd, SOL_TCP, TCP_NODELAY, (const char *)&one, sizeof(one)) < 0)
+        throw ConnPoolError(std::string("setsockopt failed"));
+    if (fcntl(listen_fd, F_SETFL, O_NONBLOCK) == -1)
+        throw ConnPoolError(std::string("unable to set nonblocking socket"));
+
+    struct sockaddr_in sockin;
+    memset(&sockin, 0, sizeof(struct sockaddr_in));
+    sockin.sin_family = AF_INET;
+    sockin.sin_addr.s_addr = INADDR_ANY;
+    sockin.sin_port = listen_addr.port;
+
+    if (bind(listen_fd, (struct sockaddr *)&sockin, sizeof(sockin)) < 0)
+        throw ConnPoolError(std::string("binding error"));
+    if (::listen(listen_fd, MAX_LISTEN_BACKLOG) < 0)
+        throw ConnPoolError(std::string("listen error"));
+    ev_listen = Event(eb, listen_fd, EV_READ,
+            std::bind(&ConnPool::accept_client, this, _1, _2));
+    ev_listen.add();
+    SALTICIDAE_LOG_INFO("listening to %u", ntohs(listen_addr.port));
+}
+
+void ConnPool::Conn::terminate() {
+    auto &pool = cpool->pool;
+    auto it = pool.find(fd);
+    if (it != pool.end())
+    {
+        /* temporarily pin the conn before it dies */
+        auto conn = it->second;
+        assert(conn == this);
+        pool.erase(it);
+        close();
+        /* inform the upper layer the connection will be destroyed */
+        on_teardown();
+        conn->self_ref = nullptr; /* remove the self-cycle */
+    }
+}
+
+void ConnPool::Conn::try_conn(evutil_socket_t, short) {
+    auto conn = self(); /* pin the connection */
+    struct sockaddr_in sockin;
+    memset(&sockin, 0, sizeof(struct sockaddr_in));
+    sockin.sin_family = AF_INET;
+    sockin.sin_addr.s_addr = addr.ip;
+    sockin.sin_port = addr.port;
+
+    if (connect(fd, (struct sockaddr *)&sockin,
+                sizeof(struct sockaddr_in)) < 0 && errno != EINPROGRESS)
+    {
+            SALTICIDAE_LOG_INFO("cannot connect to %s", std::string(addr).c_str());
+            terminate();
+            return;
+    }
+    ev_connect = Event(cpool->eb, fd, EV_WRITE,
+                std::bind(&Conn::conn_server, this, _1, _2));
+    ev_connect.add_with_timeout(CONN_SERVER_TIMEOUT);
+}
+
+ConnPool::conn_t ConnPool::create_conn(const NetAddr &addr) {
+    int fd;
+    int one = 1;
+    if ((fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
+        throw ConnPoolError(std::string("cannot create socket for remote"));
+    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&one, sizeof(one)) < 0 ||
+        setsockopt(fd, SOL_TCP, TCP_NODELAY, (const char *)&one, sizeof(one)) < 0)
+        throw ConnPoolError(std::string("setsockopt failed"));
+    if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1)
+        throw ConnPoolError(std::string("unable to set nonblocking socket"));
+    conn_t conn = create_conn();
+    Conn * conn_ptr = conn;
+    conn->fd = fd;
+    conn->cpool = this;
+    conn->mode = Conn::ACTIVE;
+    conn->addr = addr;
+    conn->ev_connect = Event(eb, -1, 0, std::bind(&Conn::try_conn, conn_ptr, _1, _2));
+    conn->ev_connect.add_with_timeout(gen_rand_timeout(TRY_CONN_DELAY));
+    add_conn(conn);
+    SALTICIDAE_LOG_INFO("created connection %s", std::string(*conn).c_str());
+    return conn;
+}
+
+ConnPool::conn_t ConnPool::add_conn(conn_t conn) {
+    auto it = pool.find(conn->fd);
+    if (it != pool.end())
+    {
+        auto old_conn = it->second;
+        old_conn->terminate();
+    }
+    return pool.insert(std::make_pair(conn->fd, conn)).first->second;
+}
+
+}