tcp syn :D
This commit is contained in:
Kevin Lange
parent
a252e54ce5
commit
4f289bd594
158
modules/rtl.c
158
modules/rtl.c
@ -53,8 +53,33 @@ static list_t * rx_wait;
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#define BROADCAST_MAC {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
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#define IPV4_PROT_UDP 17
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#define IPV4_PROT_TCP 6
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#define DHCP_MAGIC 0x63825363
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struct tcp_header {
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uint16_t source_port;
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uint16_t destination_port;
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uint32_t seq_number;
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uint32_t ack_number;
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uint16_t flags;
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uint16_t window_size;
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uint16_t checksum;
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uint16_t urgent;
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uint8_t payload[];
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} __attribute__((packed));
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struct tcp_check_header {
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uint32_t source;
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uint32_t destination;
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uint8_t zeros;
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uint8_t protocol;
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uint16_t tcp_len;
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uint8_t tcp_header[];
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};
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uint32_t ip_aton(const char * in) {
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char ip[16];
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char * c = ip;
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@ -107,6 +132,96 @@ uint16_t calculate_ipv4_checksum(struct ipv4_packet * p) {
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return ~(sum & 0xFFFF) & 0xFFFF;
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}
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uint16_t calculate_tcp_checksum(struct tcp_check_header * p, struct tcp_header * h) {
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uint32_t sum = 0;
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uint16_t * s = (uint16_t *)p;
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/* TODO: Checksums for options? */
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for (int i = 0; i < 6; ++i) {
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sum += ntohs(s[i]);
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if (sum > 0xFFFF) {
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sum = (sum >> 16) + (sum & 0xFFFF);
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}
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}
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s = (uint16_t *)h;
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for (int i = 0; i < 10; ++i) {
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sum += ntohs(s[i]);
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if (sum > 0xFFFF) {
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sum = (sum >> 16) + (sum & 0xFFFF);
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}
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}
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return ~(sum & 0xFFFF) & 0xFFFF;
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}
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#define TCP_FLAGS_SIN (1 << 1)
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#define DATA_OFFSET_5 (0x5 << 12)
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static size_t write_tcp_packet(uint8_t * buffer, uint8_t * payload, size_t payload_size) {
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size_t offset = 0;
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/* Then, let's write an ethernet frame */
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struct ethernet_packet eth_out = {
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.source = { mac[0], mac[1], mac[2], mac[3], mac[4], mac[5] },
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.destination = BROADCAST_MAC,
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.type = htons(0x0800),
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};
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memcpy(&buffer[offset], ð_out, sizeof(struct ethernet_packet));
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offset += sizeof(struct ethernet_packet);
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/* Prepare the IPv4 header */
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uint16_t _length = htons(sizeof(struct ipv4_packet) + sizeof(struct tcp_header) + payload_size);
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uint16_t _ident = htons(1);
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struct ipv4_packet ipv4_out = {
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.version_ihl = ((0x4 << 4) | (0x5 << 0)), /* 4 = ipv4, 5 = no options */
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.dscp_ecn = 0, /* not setting either of those */
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.length = _length,
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.ident = _ident,
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.flags_fragment = 0,
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.ttl = 0x40,
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.protocol = IPV4_PROT_TCP,
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.checksum = 0, /* fill this in later */
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.source = htonl(ip_aton("10.0.2.15")),
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.destination = htonl(ip_aton("37.48.83.75")),
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};
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uint16_t checksum = calculate_ipv4_checksum(&ipv4_out);
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ipv4_out.checksum = htons(checksum);
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memcpy(&buffer[offset], &ipv4_out, sizeof(struct ipv4_packet));
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offset += sizeof(struct ipv4_packet);
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struct tcp_header tcp = {
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.source_port = htons(56667), /* Ephemeral port */
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.destination_port = htons(6667), /* IRC */
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.seq_number = htonl(1),
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.ack_number = 0,
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.flags = htons(TCP_FLAGS_SIN | DATA_OFFSET_5),
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.window_size = htons(1024),
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.checksum = 0,
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.urgent = 0,
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};
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struct tcp_check_header check_hd = {
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.source = ipv4_out.source,
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.destination = ipv4_out.destination,
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.zeros = 0,
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.protocol = 6,
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.tcp_len = htons(sizeof(tcp)),
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};
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uint16_t t = calculate_tcp_checksum(&check_hd, &tcp);
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tcp.checksum = htons(t);
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memcpy(&buffer[offset], &tcp, sizeof(struct tcp_header));
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offset += sizeof(struct tcp_header);
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return offset;
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}
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static size_t write_dhcp_packet(uint8_t * buffer) {
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size_t offset = 0;
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size_t payload_size = sizeof(struct dhcp_packet);
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@ -641,6 +756,49 @@ DEFINE_SHELL_FUNCTION(rtl, "rtl8139 experiments") {
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sleep_on(rx_wait);
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parse_dns_response(tty, last_packet);
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{
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fprintf(tty, "Sending TCP syn\n");
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uint8_t payload[] = { 0 };
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size_t packet_size = write_tcp_packet(rtl_tx_buffer[next_tx], payload, 0);
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outportl(rtl_iobase + RTL_PORT_TXBUF + 4 * next_tx, rtl_tx_phys[next_tx]);
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outportl(rtl_iobase + RTL_PORT_TXSTAT + 4 * next_tx, packet_size);
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next_tx++;
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if (next_tx == 4) {
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next_tx = 0;
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}
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}
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sleep_on(rx_wait);
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{
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struct ethernet_packet * eth = (struct ethernet_packet *)last_packet;
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uint16_t eth_type = ntohs(eth->type);
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fprintf(tty, "Ethernet II, Src: (%2x:%2x:%2x:%2x:%2x:%2x), Dst: (%2x:%2x:%2x:%2x:%2x:%2x) [type=%4x)\n",
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eth->source[0], eth->source[1], eth->source[2],
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eth->source[3], eth->source[4], eth->source[5],
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eth->destination[0], eth->destination[1], eth->destination[2],
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eth->destination[3], eth->destination[4], eth->destination[5],
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eth_type);
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struct ipv4_packet * ipv4 = (struct ipv4_packet *)eth->payload;
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uint32_t src_addr = ntohl(ipv4->source);
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uint32_t dst_addr = ntohl(ipv4->destination);
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uint16_t length = ntohs(ipv4->length);
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char src_ip[16];
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char dst_ip[16];
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ip_ntoa(src_addr, src_ip);
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ip_ntoa(dst_addr, dst_ip);
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fprintf(tty, "IP packet [%s → %s] length=%d bytes\n",
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src_ip, dst_ip, length);
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}
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} else {
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return -1;
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}
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