zhhyu7 opened a new pull request, #17678:
URL: https://github.com/apache/nuttx/pull/17678
## Summary
CLOSE-WAIT - represents waiting for a connection termination request
from the local user.
TCP A TCP B
1. ESTABLISHED ESTABLISHED
2. (Close)
FIN-WAIT-1 --> <SEQ=100><ACK=300><CTL=FIN,ACK> --> CLOSE-WAIT
3. FIN-WAIT-2 <-- <SEQ=300><ACK=101><CTL=ACK> <-- CLOSE-WAIT
4. (Close)
TIME-WAIT <-- <SEQ=300><ACK=101><CTL=FIN,ACK> <-- LAST-ACK
5. TIME-WAIT --> <SEQ=101><ACK=301><CTL=ACK> --> CLOSED
6. (2 MSL)
CLOSED
in the current state, we can continue to send data until the user calls
shutdown or close, then directly enter the TCP_LAST_ACK state
## Impact
TCP supports half-open state
## Testing
sim:matter with test code
Linux TCP test code:
```
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <signal.h>
#include <stdbool.h>
#define SERVER_IP "0.0.0.0"
#define PORT 7777
#define BUFFER_SIZE 1024
bool running = true;
void signal_handler(int signum) {
printf("Signal %d received\n", signum);
running = false;
}
int main() {
int server_fd, client_fd;
struct sockaddr_in server_addr, client_addr;
socklen_t addr_len = sizeof(client_addr);
char buffer[BUFFER_SIZE] = "hello";
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("socket creation failed");
exit(EXIT_FAILURE);
}
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
if (inet_pton(AF_INET, SERVER_IP, &server_addr.sin_addr) <= 0) {
perror("invalid address");
close(server_fd);
exit(EXIT_FAILURE);
}
if (bind(server_fd, (struct sockaddr *)&server_addr,
sizeof(server_addr))) {
perror("bind failed");
close(server_fd);
exit(EXIT_FAILURE);
}
if (listen(server_fd, 5) < 0) {
perror("listen failed");
close(server_fd);
exit(EXIT_FAILURE);
}
signal(SIGTERM, signal_handler);
signal(SIGKILL, signal_handler);
signal(SIGABRT, signal_handler);
signal(SIGSEGV, signal_handler);
signal(SIGILL, signal_handler);
signal(SIGFPE, signal_handler);
signal(SIGBUS, signal_handler);
signal(SIGPIPE, signal_handler);
printf("Server listening on %s:%d\n", SERVER_IP, PORT);
while (running) {
if ((client_fd = accept(server_fd, (struct sockaddr *)&client_addr,
&addr_len)) < 0) {
perror("accept failed");
sleep(10);
}
printf("accept success\n");
sleep(1);
close(client_fd);
}
close(server_fd);
return 0;
}
```
NuttX TCP test code:
```
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <signal.h>
#include <poll.h>
#define SERVER_IP "10.0.1.1"
#define PORT 7777
#define BUFFER_SIZE 1024
void signal_handler(int signum) {
printf("Signal %d received\n", signum);
}
int main(int argc, char *argv[]) {
int sockfd;
struct sockaddr_in server_addr;
char buffer[BUFFER_SIZE];
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("socket creation failed");
exit(EXIT_FAILURE);
}
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
if (inet_pton(AF_INET, SERVER_IP, &server_addr.sin_addr) <= 0) {
perror("invalid address");
close(sockfd);
exit(EXIT_FAILURE);
}
if (connect(sockfd, (struct sockaddr *)&server_addr,
sizeof(server_addr))) {
perror("connection failed");
close(sockfd);
exit(EXIT_FAILURE);
}
signal(SIGTERM, signal_handler);
signal(SIGKILL, signal_handler);
signal(SIGABRT, signal_handler);
signal(SIGSEGV, signal_handler);
signal(SIGILL, signal_handler);
signal(SIGFPE, signal_handler);
signal(SIGBUS, signal_handler);
signal(SIGPIPE, signal_handler);
printf("Connected to server %s:%d\n", SERVER_IP, PORT);
sleep(2);
close(sockfd);
return 0;
}
```
test log, interaction process of packet capture:
```
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on nuttx0, link-type EN10MB (Ethernet), snapshot length 262144
bytes
15:29:42.198036 IP 10.0.1.2.15151 >
zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777: Flags [S], seq 1282192172, win
16384, options [mss 1460], length 0
15:29:42.198109 IP zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777 >
10.0.1.2.15151: Flags [S.], seq 66148653, ack 1282192173, win 64240, options
[mss 1460], length 0
15:29:42.198172 IP 10.0.1.2.15151 >
zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777: Flags [.], ack 1, win 16384,
length 0
15:29:43.198447 IP zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777 >
10.0.1.2.15151: Flags [F.], seq 1, ack 1, win 64240, length 0
15:29:43.402420 IP zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777 >
10.0.1.2.15151: Flags [F.], seq 1, ack 1, win 64240, length 0
15:29:43.408069 IP 10.0.1.2.15151 >
zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777: Flags [.], ack 2, win 16384,
length 0
15:29:44.207867 IP 10.0.1.2.15151 >
zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777: Flags [F.], seq 1, ack 2, win
16384, length 0
15:29:44.207923 IP zhhyu-HP-Pro-Tower-480-G9-PCI-Desktop-PC.7777 >
10.0.1.2.15151: Flags [.], ack 2, win 64240, length 0
```
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