118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
// client_udp.c
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <arpa/inet.h> // inet_pton, sockaddr_in [web:74]
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#include <sys/socket.h>
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#include <sys/types.h>
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#define BUF_SIZE 4096
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#define END_MARKER "END_OF_TRANSMISSION"
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int main(int argc, char *argv[]) {
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if (argc < 4) {
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fprintf(stderr,
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"Usage: %s <server_ip> <server_port> <input_file>\n",
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argv[0]);
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fprintf(stderr,
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"Example: %s 127.0.0.1 5000 in.txt\n",
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argv[0]);
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return -1;
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}
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const char *server_ip = argv[1];
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const char *server_port = argv[2];
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const char *input_path = argv[3];
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char *endptr = NULL;
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errno = 0;
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long port_long = strtol(server_port, &endptr, 10);
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if (errno != 0 || endptr == server_port || *endptr != '\0' ||
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port_long <= 0 || port_long > 65535) {
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fprintf(stderr, "ERROR: invalid port '%s'\n", server_port);
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return -1;
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}
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int port = (int) port_long;
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FILE *fin = fopen(input_path, "r");
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if (!fin) {
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perror("fopen(input_file)");
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return -1;
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}
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int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
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if (sockfd < 0) {
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perror("socket");
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fclose(fin);
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return -1;
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}
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struct sockaddr_in servaddr;
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memset(&servaddr, 0, sizeof(servaddr));
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servaddr.sin_family = AF_INET;
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servaddr.sin_port = htons(port);
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if (inet_pton(AF_INET, server_ip, &servaddr.sin_addr) != 1) {
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fprintf(stderr, "ERROR: invalid IP address '%s'\n", server_ip);
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close(sockfd);
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fclose(fin);
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return -1;
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}
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char buf[BUF_SIZE];
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for (;;) {
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size_t n = fread(buf, 1, sizeof(buf), fin);
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if (n > 0) {
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ssize_t sent = sendto(sockfd,
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buf,
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n,
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0,
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(struct sockaddr *) &servaddr,
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sizeof(servaddr));
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if (sent < 0 || (size_t) sent != n) {
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perror("sendto");
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close(sockfd);
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fclose(fin);
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return -1;
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}
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}
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if (n < sizeof(buf)) {
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if (ferror(fin)) {
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perror("fread");
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close(sockfd);
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fclose(fin);
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return -1;
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}
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break;
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}
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}
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if (fclose(fin) == EOF) {
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perror("fclose(input_file)");
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}
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ssize_t sent = sendto(sockfd,
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END_MARKER,
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strlen(END_MARKER),
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0,
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(struct sockaddr *) &servaddr,
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sizeof(servaddr));
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if (sent < 0 || (size_t) sent != strlen(END_MARKER)) {
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perror("sendto(END_MARKER)");
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close(sockfd);
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return -1;
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}
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printf("File '%s' sent to %s:%d, END marker transmitted.\n",
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input_path, server_ip, port);
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close(sockfd);
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return 0;
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}
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