karchnu/some-usable-scripts
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paintest now handles network communications (UDP).

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This commit is contained in:
Philippe Pittoli 2024-12-21 17:11:22 +01:00
parent a714806034
commit 424078c615
1 changed files with 122 additions and 9 deletions
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121
c/paintest.c
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@ -3,6 +3,8 @@
#include <unistd.h> // read write
#include <stdlib.h>
#include <netdb.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
@ -164,8 +166,119 @@ void unixsock_client(char *address) {
close(data_socket);
}
void network(char *address) {
printf("network: %s\n", address);
void network_client(char *address, char *port) {
printf("network_client: @%s port %s\n", address, port);
int sfd, s;
char buffer[BUFFER_SIZE];
ssize_t nread;
struct addrinfo hints;
struct addrinfo *result, *rp;
/* Obtain address(es) matching host/port. */
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC; /* Allow IPv4 or IPv6 */
hints.ai_socktype = SOCK_DGRAM; /* Datagram socket */
hints.ai_flags = 0;
hints.ai_protocol = 0; /* Any protocol */
s = getaddrinfo(address, port, &hints, &result);
if (s != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
exit(EXIT_FAILURE);
}
/* getaddrinfo() returns a list of address structures.
Try each address until we successfully connect(2).
If socket(2) (or connect(2)) fails, we (close the socket and) try the next address. */
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sfd == -1) continue;
if (connect(sfd, rp->ai_addr, rp->ai_addrlen) != -1) break;
close(sfd);
}
freeaddrinfo(result); /* No longer needed */
if (rp == NULL) { /* No address succeeded */
fprintf(stderr, "Could not connect\n");
exit(EXIT_FAILURE);
}
snprintf(buffer, 6, "hello");
if (write(sfd, buffer, 6) != 6) {
fprintf(stderr, "partial/failed write\n");
exit(EXIT_FAILURE);
}
nread = read(sfd, buffer, BUFFER_SIZE);
if (nread == -1) {
perror("read");
exit(EXIT_FAILURE);
}
printf("received %zd bytes: %s\n", nread, buffer);
}
void network_server(char *port) {
printf("network_server: %s\n", port);
int sfd, s;
char buffer[BUFFER_SIZE];
ssize_t nread;
socklen_t peer_addrlen;
struct addrinfo hints;
struct addrinfo *result, *rp;
struct sockaddr_storage peer_addr;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC; /* Allow IPv4 or IPv6 */
hints.ai_socktype = SOCK_DGRAM; /* Datagram socket */
hints.ai_flags = AI_PASSIVE; /* For wildcard IP address */
hints.ai_protocol = 0; /* Any protocol */
hints.ai_canonname = NULL;
hints.ai_addr = NULL;
hints.ai_next = NULL;
s = getaddrinfo(NULL, port, &hints, &result);
if (s != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
exit(EXIT_FAILURE);
}
/* getaddrinfo() returns a list of address structures.
Try each address until we successfully bind(2).
If socket(2) (or bind(2)) fails, we (close the socket and) try the next address. */
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sfd == -1) continue;
if (bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) break;
close(sfd);
}
freeaddrinfo(result); /* No longer needed */
if (rp == NULL) { /* No address succeeded */
fprintf(stderr, "Could not bind\n");
exit(EXIT_FAILURE);
}
/* Read a single datagram and echo it back to sender. */
char host[NI_MAXHOST], service[NI_MAXSERV];
peer_addrlen = sizeof(peer_addr);
nread = recvfrom(sfd, buffer, BUFFER_SIZE, 0, (struct sockaddr *) &peer_addr, &peer_addrlen);
if (nread == -1) {
fprintf(stderr, "nread == -1\n");
exit(EXIT_FAILURE);
}
s = getnameinfo((struct sockaddr *) &peer_addr, peer_addrlen, host, NI_MAXHOST, service, NI_MAXSERV, NI_NUMERICSERV);
if (s == 0) printf("Received %zd bytes from %s:%s\n", nread, host, service);
else fprintf(stderr, "getnameinfo: %s\n", gai_strerror(s));
printf("sending it back to sender\n");
if (sendto(sfd, buffer, nread, 0, (struct sockaddr *) &peer_addr, peer_addrlen) != nread) {
fprintf(stderr, "Error sending response\n");
}
}
void usage(void) {
@ -181,10 +294,10 @@ int main(int argc, char **argv)
}
while (i != argc) {
//
if (memcmp(argv[i], "r", 1) == 0) { read_file(argv[i+1]); }
else if (memcmp(argv[i], "w", 1) == 0) { write_file(argv[i+1]); }
else if (memcmp(argv[i], "n", 1) == 0) { network(argv[i+1]); }
else if (memcmp(argv[i], "n", 1) == 0) { network_client(argv[i+1], argv[i+2]); i++; }
else if (memcmp(argv[i], "N", 1) == 0) { network_server(argv[i+1]); }
else if (memcmp(argv[i], "u", 1) == 0) { unixsock_client(argv[i+1]); }
else if (memcmp(argv[i], "U", 1) == 0) { unixsock_server(argv[i+1]); }
else if (memcmp(argv[i], "h", 1) == 0) { usage(); }