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KA10: Added inbound FTP Port translation for NAT.

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This commit is contained in:
Richard Cornwell
2019-03-10 15:13:50 -04:00
parent a15f42686e
commit f67222e936
1 changed files with 104 additions and 19 deletions
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123
PDP10/ka10_imp.c
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@@ -320,7 +320,8 @@ struct imp_packet {
} imp_buffer[8];
struct imp_map {
uint16 port; /* Port to fix */
uint16 sport; /* Port to fix */
uint16 dport; /* Port to fix */
uint16 cls_tim; /* Close timer */
uint32 adj; /* Amount to adjust */
uint32 lseq; /* Sequence number last adjusted */
@@ -713,7 +714,8 @@ imp_timer_task(struct imp_device *imp)
for (n = 0; n < 64; n++) {
if (imp->port_map[n].cls_tim > 0) {
if (--imp->port_map[n].cls_tim == 0) {
imp->port_map[n].port = 0;
imp->port_map[n].dport = 0;
imp->port_map[n].sport = 0;
imp->port_map[n].adj = 0;
}
}
@@ -750,7 +752,7 @@ imp_packet_in(struct imp_device *imp)
int type;
int n;
int pad;
//int i;
int i;
if (eth_read (&imp_data.etherface, &read_buffer, NULL) <= 0)
return;
hdr = (struct imp_eth_hdr *)(&read_buffer.msg[0]);
@@ -811,21 +813,28 @@ imp_packet_in(struct imp_device *imp)
/* If TCP packet update the TCP checksum */
if (ip_hdr->ip_p == TCP_PROTO) {
struct tcp *tcp_hdr = (struct tcp *)payload;
uint16 port = ntohs(tcp_hdr->tcp_dport);
uint16 dport = ntohs(tcp_hdr->tcp_dport);
uint16 sport = ntohs(tcp_hdr->tcp_sport);
int thl = ((ntohs(tcp_hdr->flags) >> 12) & 0xf) * 4;
int hl = (ip_hdr->ip_v_hl & 0xf) * 4;
uint8 *tcp_payload = &imp->rbuffer[
sizeof(struct imp_eth_hdr) + hl + thl];
checksumadjust((uint8 *)&tcp_hdr->chksum,
(uint8 *)(&ip_hdr->ip_dst), sizeof(in_addr_t),
(uint8 *)(&imp_data.hostip), sizeof(in_addr_t));
if ((ntohs(tcp_hdr->flags) & 0x10) != 0) {
//fprintf(stderr, "ACK %x\r\n", port);
//fprintf(stderr, "ACK %d %d\r\n", sport, dport);
for (n = 0; n < 64; n++) {
if (imp->port_map[n].port == port) {
if (imp->port_map[n].sport == sport &&
imp->port_map[n].dport == dport) {
/* Check if SYN */
if (ntohs(tcp_hdr->flags) & 02) {
imp->port_map[n].port = 0;
imp->port_map[n].sport = 0;
imp->port_map[n].dport = 0;
imp->port_map[n].adj = 0;
} else {
uint32 new_seq = ntohl(tcp_hdr->ack);
//fprintf(stderr, "Adjusting sequence %x %d %x\r\n", port, imp->port_map[i].adj, new_seq);
//fprintf(stderr, "Adjusting sequence %x %d %x\r\n", sport, imp->port_map[n].adj, new_seq);
if (new_seq > imp->port_map[n].lseq) {
new_seq = htonl(new_seq - imp->port_map[n].adj);
checksumadjust((uint8 *)&tcp_hdr->chksum,
@@ -833,13 +842,85 @@ imp_packet_in(struct imp_device *imp)
(uint8 *)(&new_seq), 4);
tcp_hdr->ack = new_seq;
}
//fprintf(stderr, "Adjusting sequence %x %d %x\r\n", port, imp->port_map[i].adj, new_seq);
//fprintf(stderr, "Adjusting sequence %x %d %x\r\n", sport, imp->port_map[n].adj, new_seq);
}
if (ntohs(tcp_hdr->flags) & 01)
imp->port_map[n].cls_tim = 100;
break;
}
}
}
/* Check if recieving to FTP */
if (sport == 21 && strncmp(&tcp_payload[0], "PORT ", 5) == 0) {
/* We need to translate the IP address to new port number. */
int l = ntohs(ip_hdr->ip_len) - thl - hl;
uint32 nip = ntohl(imp->hostip);
uint16 len;
int nlen;
int i;
uint8 port_buffer[100];
struct udp_hdr udp_hdr;
// fprintf(stderr, "pktx Len=%d %d %d %d: ", read_buffer.len, hl, thl, l);
// for (i = sizeof(struct imp_eth_hdr); i < read_buffer.len; i++)
// fprintf(stderr, "%02x ", imp->rbuffer[i]);
// fprintf(stderr, "\r\n");
//fprintf(stderr, "Port: %d %s\r\n", l, tcp_payload);
/* Count out 4 commas */
for (i = nlen = 0; i < l && nlen < 4; i++) {
if (tcp_payload[i] == ',')
nlen++;
}
nlen = sprintf(port_buffer, "PORT %d,%d,%d,%d,",
(nip >> 24) & 0xFF, (nip >> 16) & 0xFF,
(nip >> 8) & 0xFF, nip&0xff);
/* Copy over rest of string */
while(i < l) {
port_buffer[nlen++] = tcp_payload[i++];
}
port_buffer[nlen] = '\0';
memcpy(tcp_payload, port_buffer, nlen);
/* Check if we need to update the sequence numbers */
if (nlen != l && (ntohs(tcp_hdr->flags) & 02) == 0) {
int n = -1;
/* See if we need to change the sequence number */
for (i = 0; i < 64; i++) {
if (imp->port_map[i].sport == sport &&
imp->port_map[i].dport == dport) {
n = i;
break;
}
if (n < 0 && imp->port_map[i].dport == 0)
n = 0;
}
if (n >= 0) {
//fprintf(stderr, "old sequence %x %d\r\n", dport, imp->port_map[n].adj);
imp->port_map[n].dport = dport;
imp->port_map[n].sport = sport;
imp->port_map[n].adj += nlen - l;
imp->port_map[n].cls_tim = 0;
imp->port_map[n].lseq = ntohl(tcp_hdr->seq);
//fprintf(stderr, "Adjusting sequence %x %d\r\n", dport, imp->port_map[n].adj);
}
}
/* Now we need to update the checksums */
tcp_hdr->chksum = 0;
ip_hdr->ip_len = htons(nlen + thl + hl);
ip_checksum((uint8 *)&tcp_hdr->chksum, (uint8 *)tcp_hdr,
nlen + thl);
udp_hdr.ip_src = ip_hdr->ip_src;
udp_hdr.ip_dst = imp->hostip;
udp_hdr.zero = 0;
udp_hdr.proto = TCP_PROTO;
udp_hdr.hlen = htons(nlen + thl);
checksumadjust((uint8 *)&tcp_hdr->chksum, (uint8 *)(&udp_hdr), 0,
(uint8 *)(&udp_hdr), sizeof(udp_hdr));
//fprintf(stderr, "Port: %d %s\r\n", nlen, tcp_payload);
ip_hdr->ip_sum = 0;
ip_checksum((uint8 *)(&ip_hdr->ip_sum), (uint8 *)ip_hdr, 20);
// fprintf(stderr, "pkty Len=%d %d %d %d: ", read_buffer.len, hl, thl, l);
// for (i = sizeof(struct imp_eth_hdr); i < read_buffer.len; i++)
// fprintf(stderr, "%02x ", imp->rbuffer[i]);
// fprintf(stderr, "\r\n");
}
/* Check if UDP */
} else if (ip_hdr->ip_p == UDP_PROTO) {
@@ -978,7 +1059,8 @@ imp_packet_out(struct imp_device *imp, ETH_PACK *packet) {
if (pkt->iphdr.ip_p == TCP_PROTO) {
struct tcp *tcp_hdr = (struct tcp *)payload;
int thl = ((ntohs(tcp_hdr->flags) >> 12) & 0xf) * 4;
uint16 port = ntohs(tcp_hdr->tcp_sport);
uint16 sport = ntohs(tcp_hdr->tcp_sport);
uint16 dport = ntohs(tcp_hdr->tcp_dport);
uint8 *tcp_payload = &packet->msg[
sizeof(struct imp_eth_hdr) + hl + thl];
/* Update pseudo header checksum */
@@ -987,10 +1069,12 @@ imp_packet_out(struct imp_device *imp, ETH_PACK *packet) {
(uint8 *)(&imp->ip), sizeof(in_addr_t));
/* See if we need to change the sequence number */
for (i = 0; i < 64; i++) {
if (imp->port_map[i].port == port) {
if (imp->port_map[i].sport == sport &&
imp->port_map[i].dport == dport) {
/* Check if SYN */
if (ntohs(tcp_hdr->flags) & 02) {
imp->port_map[i].port = 0;
imp->port_map[i].sport = 0;
imp->port_map[i].dport = 0;
imp->port_map[i].adj = 0;
} else {
uint32 new_seq = ntohl(tcp_hdr->seq);
@@ -1009,8 +1093,7 @@ imp_packet_out(struct imp_device *imp, ETH_PACK *packet) {
}
}
/* Check if sending to FTP */
if (ntohs(tcp_hdr->tcp_dport) == 21 &&
strncmp(&tcp_payload[0], "PORT ", 5) == 0) {
if (dport == 21 && strncmp(&tcp_payload[0], "PORT ", 5) == 0) {
/* We need to translate the IP address to new port number. */
int l = ntohs(pkt->iphdr.ip_len) - thl - hl;
uint32 nip = ntohl(imp->ip);
@@ -1042,20 +1125,22 @@ imp_packet_out(struct imp_device *imp, ETH_PACK *packet) {
int n = -1;
/* See if we need to change the sequence number */
for (i = 0; i < 64; i++) {
if (imp->port_map[i].port == port) {
if (imp->port_map[i].sport == sport &&
imp->port_map[i].dport == dport) {
n = i;
break;
}
if (n < 0 && imp->port_map[i].port == 0)
if (n < 0 && imp->port_map[i].dport == 0)
n = 0;
}
if (n >= 0) {
//fprintf(stderr, "old sequence %x %d\r\n", port, imp->port_map[n].adj);
imp->port_map[n].port = port;
//fprintf(stderr, "old sequence %x %d\r\n", sport, imp->port_map[n].adj);
imp->port_map[n].dport = dport;
imp->port_map[n].sport = sport;
imp->port_map[n].adj += nlen - l;
imp->port_map[n].cls_tim = 0;
imp->port_map[n].lseq = ntohl(tcp_hdr->seq);
//fprintf(stderr, "Adjusting sequence %x %d\r\n", port, imp->port_map[n].adj);
//fprintf(stderr, "Adjusting sequence %x %d\r\n", sport, imp->port_map[n].adj);
}
}
/* Now we need to update the checksums */