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Clean up TCP code

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This commit is contained in:
Mark
2020-03-24 17:03:19 +02:00
parent 282ebe0e5e
commit 3905d0ca1a
2 changed files with 80 additions and 61 deletions
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include/net/tcp.h
+12 -8
View File
@@ -1,6 +1,17 @@
#pragma once
#include "sys/types.h"
struct tcp_flags {
uint8_t fin:1;
uint8_t syn:1;
uint8_t rst:1;
uint8_t psh:1;
uint8_t ack:1;
uint8_t urg:1;
uint8_t ece:1;
uint8_t cwr:1;
} __attribute__((packed));
struct tcp_frame {
uint16_t src_port;
uint16_t dst_port;
@@ -9,14 +20,7 @@ struct tcp_frame {
uint8_t ns:1;
uint8_t zero:3;
uint8_t doff:4;
uint8_t fin:1;
uint8_t syn:1;
uint8_t rst:1;
uint8_t psh:1;
uint8_t ack:1;
uint8_t urg:1;
uint8_t ece:1;
uint8_t cwr:1;
struct tcp_flags flags;
uint16_t window;
uint16_t checksum;
uint16_t urg_ptr;
net/tcp.c
+68 -53
View File
@@ -1,6 +1,7 @@
#include "net/packet.h"
#include "sys/string.h"
#include "sys/debug.h"
#include "sys/panic.h"
#include "net/inet.h"
#include "net/util.h"
#include "sys/attr.h"
@@ -51,60 +52,39 @@ static uint16_t tcp_checksum(uint32_t daddr, uint32_t saddr, uint16_t tcp_length
}
// Reset a connection attempt given its SYN packet
static void tcp_syn_reset(struct netdev *dev, uint32_t inaddr, struct tcp_frame *syn_frame) {
static void tcp_packet_send(struct netdev *dev,
struct tcp_socket *sock,
struct tcp_flags flags,
const void *data,
size_t len) {
if (!(dev->flags & IF_F_HASIP)) {
return;
}
char packet[sizeof(struct eth_frame) + sizeof(struct inet_frame) + sizeof(struct tcp_frame)];
struct tcp_frame *tcp = (struct tcp_frame *) &packet[sizeof(struct eth_frame) + sizeof(struct inet_frame)];
char packet[sizeof(struct eth_frame) +
sizeof(struct inet_frame) +
sizeof(struct tcp_frame) +
len];
struct tcp_frame *tcp = (struct tcp_frame *) &packet[sizeof(struct eth_frame) +
sizeof(struct inet_frame)];
void *dst_data = &packet[sizeof(struct eth_frame) +
sizeof(struct inet_frame) +
sizeof(struct tcp_frame)];
memset(tcp, 0, sizeof(struct tcp_frame));
memcpy(dst_data, data, len);
tcp->src_port = syn_frame->dst_port;
tcp->dst_port = syn_frame->src_port;
tcp->ack_seq = htonl(ntohl(syn_frame->seq) + 1);
tcp->src_port = htons(sock->local_port);
tcp->dst_port = htons(sock->remote_port);
tcp->seq = htonl(sock->local_seq);
tcp->ack_seq = htonl(sock->remote_seq);
tcp->doff = sizeof(struct tcp_frame) / 4;
tcp->rst = 1;
tcp->ack = 1;
tcp->window = syn_frame->window;
tcp->flags = flags;
tcp->window = htons(64400);
uint16_t checksum = tcp_checksum(inaddr, dev->inaddr, sizeof(struct tcp_frame), tcp);
uint16_t checksum = tcp_checksum(sock->remote_inaddr, dev->inaddr, sizeof(struct tcp_frame), tcp);
tcp->checksum = htons(checksum);
debug_dump(DEBUG_DEFAULT, tcp, sizeof(struct tcp_frame));
inet_send_wrapped(dev, inaddr, INET_P_TCP, packet, sizeof(packet));
}
// Establish a remote -> local connection given its SYN packet
static void tcp_server_establish(struct netdev *dev, uint32_t inaddr, struct tcp_frame *syn, struct tcp_socket *serv) {
client.local_seq = 32657;
client.local_port = serv->local_port;
client.remote_seq = ntohl(syn->seq);
client.remote_port = ntohs(syn->src_port);
client.remote_inaddr = inaddr;
client.state = TCP_STA_SYNACK_SENT;
client.type = TCP_SOCK_CLIENT;
char packet[sizeof(struct eth_frame) + sizeof(struct inet_frame) + sizeof(struct tcp_frame)];
struct tcp_frame *tcp = (struct tcp_frame *) &packet[sizeof(struct eth_frame) + sizeof(struct inet_frame)];
memset(tcp, 0, sizeof(struct tcp_frame));
tcp->src_port = ntohs(client.local_port);
tcp->dst_port = ntohs(client.remote_port);
tcp->seq = htonl(client.local_seq);
tcp->ack_seq = htonl(++client.remote_seq);
tcp->doff = sizeof(struct tcp_frame) / 4;
tcp->ack = 1;
tcp->syn = 1;
tcp->window = syn->window;
uint16_t checksum = tcp_checksum(inaddr, dev->inaddr, sizeof(struct tcp_frame), tcp);
tcp->checksum = htons(checksum);
kdebug("establish " FMT_INADDR ":%u -> :%u\n", VA_INADDR(inaddr), client.remote_port, client.local_port);
inet_send_wrapped(dev, client.remote_inaddr, INET_P_TCP, packet, sizeof(packet));
inet_send_wrapped(dev, sock->remote_inaddr, INET_P_TCP, packet, sizeof(packet));
}
void tcp_handle_frame(struct packet *p, struct eth_frame *eth, struct inet_frame *ip, void *data, size_t len) {
@@ -125,40 +105,75 @@ void tcp_handle_frame(struct packet *p, struct eth_frame *eth, struct inet_frame
len -= frame_size;
uint16_t port = ntohs(tcp->dst_port);
if (tcp->syn && !tcp->ack) {
if (tcp->flags.syn && !tcp->flags.ack) {
if (port == 9000) {
tcp_server_establish(p->dev, ntohl(ip->src_inaddr), tcp, &port9000);
// Establish local->remote connection
client.local_seq = 32657;
client.local_port = port9000.local_port;
client.remote_seq = ntohl(tcp->seq);
client.remote_port = ntohs(tcp->src_port);
client.remote_inaddr = ntohl(ip->src_inaddr);
client.state = TCP_STA_SYNACK_SENT;
client.type = TCP_SOCK_CLIENT;
// Reply with SYN+ACK
struct tcp_flags flags = {
.syn = 1,
.ack = 1
};
++client.remote_seq;
tcp_packet_send(p->dev, &client, flags, NULL, 0);
} else {
tcp_syn_reset(p->dev, ntohl(ip->src_inaddr), tcp);
// Reply with ACK+RST
// tcp_syn_reset(p->dev, ntohl(ip->src_inaddr), tcp);
}
} else if (tcp->ack && !tcp->syn && !tcp->psh) {
} else if (tcp->flags.ack && !tcp->flags.syn && !tcp->flags.psh) {
uint16_t remote_port = ntohs(tcp->src_port);
uint32_t remote_inaddr = ntohl(ip->src_inaddr);
if (port == 9000 && remote_port == client.remote_port && remote_inaddr == client.remote_inaddr) {
if (client.state == TCP_STA_SYNACK_SENT) {
kdebug("Remote side confirmed establishing\n");
client.local_seq = 1;
client.remote_seq = 1;
client.state = TCP_STA_ESTABLISHED;
++client.local_seq;
} else {
kwarn("Got ACK, but was not waiting for it\n");
}
}
} else if (tcp->ack && tcp->psh) {
} else if (tcp->flags.ack && tcp->flags.psh) {
uint16_t remote_port = ntohs(tcp->src_port);
uint32_t remote_inaddr = ntohl(ip->src_inaddr);
uint32_t segment_seq = ntohl(tcp->seq);
if (segment_seq < client.remote_seq) {
panic("TODO: handle this\n");
}
if (port == 9000 && remote_port == client.remote_port && remote_inaddr == client.remote_inaddr) {
if (client.state == TCP_STA_ESTABLISHED) {
kdebug("Got PSH+ACK on established socket\n");
kdebug("Length = %u\n", len);
uint32_t rel_seq = segment_seq - client.remote_seq;
kdebug("Seq %u:%u\n", rel_seq, rel_seq + len);
if (rel_seq != 0) {
panic("TODO: out-of-order segment reception\n");
}
debug_dump(DEBUG_DEFAULT, data, len);
// Reply with ACK
struct tcp_flags flags = {
.ack = 1
};
client.remote_seq += len;
tcp_packet_send(p->dev, &client, flags, NULL, 0);
} else {
kwarn("Got PSH+ACK, but socket is not established\n");
}
}
} else {
kwarn("%s: unhandled packet: syn=%d, ack=%d, psh=%d, rst=%d\n", tcp->syn, tcp->ack, tcp->psh, tcp->rst);
kwarn("%s: unhandled packet: syn=%d, ack=%d, psh=%d, rst=%d\n",
tcp->flags.syn,
tcp->flags.ack,
tcp->flags.psh,
tcp->flags.rst);
}
}