Improve TCP blocking of requests

4 files changed, 43 insertions, 30 deletions

diff --git a/kernel/network/tcp.c b/kernel/network/tcp.c
index fc8d97c..d171722 100644
--- a/kernel/network/tcp.c
+++ b/kernel/network/tcp.c
@@ -134,25 +134,32 @@ static void tcp_send(struct TcpConnection *con, u8 *buffer, u16 length,
 }
 
 void tcp_resend_packets(struct TcpConnection *con) {
-  if (con->inflight.num_entries > 0) {
-    for (u32 i = 0;; i++) {
-      struct TcpPacket *packet;
-      int end;
-      if (!relist_get(&con->inflight, i, (void *)&packet, &end)) {
-        if (end) {
-          break;
-        }
-        continue;
-      }
-      if (packet->time + 200 > pit_num_ms()) {
-        continue;
+  if (0 == con->inflight.num_entries) {
+    return;
+  }
+  int did_resend = 0;
+  for (u32 i = 0;; i++) {
+    struct TcpPacket *packet;
+    int end;
+    if (!relist_get(&con->inflight, i, (void *)&packet, &end)) {
+      if (end) {
+        break;
       }
-      // resend the packet
-      relist_remove(&con->inflight, i);
-      tcp_send(con, packet->buffer, packet->length, packet->seq_num,
-               packet->payload_length);
-      kfree(packet);
+      continue;
+    }
+    if (packet->time + 200 > pit_num_ms()) {
+      continue;
     }
+    // resend the packet
+    did_resend = 1;
+    relist_remove(&con->inflight, i);
+    tcp_send(con, packet->buffer, packet->length, packet->seq_num,
+             packet->payload_length);
+    kfree(packet);
+  }
+  if (did_resend) {
+    con->max_inflight = 1;
+    con->window_size = MSS;
   }
 }
 
@@ -194,21 +201,17 @@ void tcp_send_syn(struct TcpConnection *con) {
   con->seq++;
 }
 
-int tcp_can_send(struct TcpConnection *con, u16 payload_length) {
-  if (con->inflight.num_entries > 2) {
+u16 tcp_can_send(struct TcpConnection *con) {
+  if (con->inflight.num_entries > con->max_inflight) {
     tcp_resend_packets(con);
     return 0;
   }
-  if (con->seq - con->seq_ack + payload_length > con->current_window_size) {
-    tcp_resend_packets(con);
-    return 0;
-  }
-  return 1;
+  return con->current_window_size;
 }
 
 int send_tcp_packet(struct TcpConnection *con, const u8 *payload,
                     u16 payload_length) {
-  if (!tcp_can_send(con, payload_length)) {
+  if (0 == tcp_can_send(con)) {
     return 0;
   }
 
@@ -326,7 +329,7 @@ void handle_tcp(ipv4_t src_ip, ipv4_t dst_ip, const u8 *payload,
           }
           continue;
         }
-        if (packet->seq_num + packet->payload_length != ack_num) {
+        if (packet->seq_num + packet->payload_length > ack_num) {
           continue;
         }
         relist_remove(&incoming_connection->inflight, i);
@@ -337,6 +340,7 @@ void handle_tcp(ipv4_t src_ip, ipv4_t dst_ip, const u8 *payload,
     }
     tcp_resend_packets(incoming_connection);
     if (0 == incoming_connection->inflight.num_entries) {
+      incoming_connection->max_inflight++;
       u32 rest = incoming_connection->window_size -
                  incoming_connection->current_window_size;
       if (rest > 0) {
diff --git a/kernel/network/tcp.h b/kernel/network/tcp.h
index 836a148..ec253bd 100644
--- a/kernel/network/tcp.h
+++ b/kernel/network/tcp.h
@@ -6,4 +6,4 @@ void handle_tcp(ipv4_t src_ip, ipv4_t dst_ip, const u8 *payload, u32 payload_len
 int send_tcp_packet(struct TcpConnection *con, const u8 *payload,
                     u16 payload_length);
 void tcp_close_connection(struct TcpConnection *con);
-int tcp_can_send(struct TcpConnection *con, u16 payload_length);
+u16 tcp_can_send(struct TcpConnection *con);
diff --git a/kernel/socket.c b/kernel/socket.c
index 8b6e12d..79121e7 100644
--- a/kernel/socket.c
+++ b/kernel/socket.c
@@ -99,6 +99,7 @@ struct TcpConnection *internal_tcp_incoming(u32 src_ip, u16 src_port,
   ringbuffer_init(&con->incoming_buffer, 8192);
   ringbuffer_init(&con->outgoing_buffer, 8192);
   relist_init(&con->inflight);
+  con->max_inflight = 1;
   stack_push(&listen->incoming_connections, con);
   return con;
 }
@@ -116,7 +117,8 @@ int tcp_sync_buffer(vfs_fd_t *fd) {
     return 0;
   }
 
-  if (!tcp_can_send(con, send_buffer_len)) {
+  send_buffer_len = min(tcp_can_send(con), send_buffer_len);
+  if(0 == send_buffer_len) {
     return 0;
   }
 
@@ -157,6 +159,11 @@ int tcp_write(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
     return -EBADF; // TODO: Check if this is correct.
   }
 
+  len = min(len, tcp_can_send(con));
+  if (0 == len) {
+    return -EWOULDBLOCK;
+  }
+
   if (con->no_delay) {
     if (!send_tcp_packet(con, buffer, len)) {
       return -EWOULDBLOCK;
@@ -187,10 +194,10 @@ int tcp_has_data(vfs_inode_t *inode) {
 int tcp_can_write(vfs_inode_t *inode) {
   struct TcpConnection *con = inode->internal_object;
   if (con->no_delay) {
-    return tcp_can_send(con, 256);
+    return (0 != tcp_can_send(con));
   }
   return (ringbuffer_unused(&con->outgoing_buffer) > 0) ||
-         (tcp_can_send(con, 250));
+         (0 != tcp_can_send(con));
 }
 
 int udp_recvfrom(vfs_fd_t *fd, void *buffer, size_t len, int flags,
@@ -317,6 +324,7 @@ int tcp_connect(vfs_fd_t *fd, const struct sockaddr *addr, socklen_t addrlen) {
   ringbuffer_init(&con->outgoing_buffer, 8192);
   list_add(&open_tcp_connections, con, NULL);
   relist_init(&con->inflight);
+  con->max_inflight = 1;
 
   tcp_send_syn(con);
 
diff --git a/kernel/socket.h b/kernel/socket.h
index f41e9a1..0cb6865 100644
--- a/kernel/socket.h
+++ b/kernel/socket.h
@@ -53,6 +53,7 @@ struct TcpConnection {
   struct ringbuffer outgoing_buffer;
 
   struct relist inflight;
+  u8 max_inflight;
 
   int no_delay;