Stowage/v86
2
0
Fork 0
mirror of https://github.com/copy/v86.git synced 2025-12-31 04:23:15 +00:00
Code Issues Projects Releases Packages Wiki Activity

implement tcp mss option and set it based on the mtu

Browse source
This commit is contained in:
ading2210 2025-11-06 16:33:23 -08:00 • committed by Fabian
parent 0beafeee07
commit 1a1afab08d
1 changed files with 32 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

37
src/browser/fake_network.js
View file

@ -192,6 +192,17 @@ function view_set_array(offset, data, view, out)
return data.length;
}
/**
* Write zeros into the view starting at offset
* @param {number} offset
* @param {number} length
* @param {DataView} view
*/
function view_set_zeros(offset, length, view, out)
{
out.eth_frame.fill(0, view.byteOffset + offset, view.byteOffset + offset + length);
}
/**
* UTF8-encode given string into view starting at offset, return number of bytes written.
*
@ -951,19 +962,31 @@ function write_tcp(spec, out) {
if(tcp.ece) flags |= 0x40;
if(tcp.cwr) flags |= 0x80;
const doff = TCP_HEADER_SIZE >> 2; // header length in 32-bit words
let doff = TCP_HEADER_SIZE;
if (tcp.options) {
if (tcp.options.mss) {
view.setUint8(doff, 0x02) //mss option type
view.setUint8(doff + 1, 0x04) //option length
view.setUint16(doff + 2, tcp.options.mss);
doff += 4;
}
}
let total_length = Math.ceil(doff / 4) * 4; // needs to a multiple of 4 bytes
if (tcp.options && total_length - doff > 0) {
view_set_zeros(doff, total_length - doff, view, out); //write zeros into remaining space for options
}
view.setUint16(0, tcp.sport);
view.setUint16(2, tcp.dport);
view.setUint32(4, tcp.seq);
view.setUint32(8, tcp.ackn);
view.setUint8(12, doff << 4);
view.setUint8(12, (total_length >> 2) << 4); // header length in 32-bit words
view.setUint8(13, flags);
view.setUint16(14, tcp.winsize);
view.setUint16(16, 0); // checksum initially zero before calculation
view.setUint16(18, tcp.urgent || 0);
let total_length = TCP_HEADER_SIZE;
if(spec.tcp_data) {
total_length += view_set_array(TCP_HEADER_SIZE, spec.tcp_data, view, out);
}
@ -1020,7 +1043,8 @@ export function fake_tcp_probe(dport, adapter) {
*/
export function TCPConnection(adapter)
{
const IPV4_PAYLOAD_SIZE = (adapter.mtu || MTU_DEFAULT) - IPV4_HEADER_SIZE;
this.mtu = (adapter.mtu || MTU_DEFAULT);
const IPV4_PAYLOAD_SIZE = this.mtu - IPV4_HEADER_SIZE;
const TCP_PAYLOAD_SIZE = IPV4_PAYLOAD_SIZE - TCP_HEADER_SIZE;
this.state = TCP_STATE_CLOSED;
@ -1123,7 +1147,10 @@ TCPConnection.prototype.accept = function(packet) {
ackn: this.ack,
winsize: packet.tcp.winsize,
syn: true,
ack: true
ack: true,
options: {
mss: (this.mtu - TCP_HEADER_SIZE - IPV4_HEADER_SIZE)
}
};
// dbg_log(`TCP[${this.tuple}]: accept(): sending SYN+ACK in state "${this.state}", next "${TCP_STATE_ESTABLISHED}"`, LOG_FETCH);
this.state = TCP_STATE_ESTABLISHED;