70 lines
1.9 KiB
C
70 lines
1.9 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <netdb.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <unistd.h>
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bool has_internet() {
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int ret;
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// https://www.man7.org/linux/man-pages/man3/getaddrinfo.3.html
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struct addrinfo hints;
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = AF_INET;
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hints.ai_socktype = SOCK_STREAM;
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hints.ai_flags = 0;
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hints.ai_protocol = 0;
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struct addrinfo *res, *rp;
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ret = getaddrinfo("hopeless-cloud.xyz", "80", 0, &res);
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if (ret != 0) {
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// fprintf(stderr, "Couldn't getaddrinfo()\n");
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return false;
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}
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int sockfd;
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for (rp = res; rp != NULL; rp = rp->ai_next) {
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// https://www.man7.org/linux/man-pages/man2/socket.2.html
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sockfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
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if (sockfd == -1) { continue; }
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// https://www.man7.org/linux/man-pages/man2/connect.2.html
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if (connect(sockfd, rp->ai_addr, rp->ai_addrlen) == 0) { break; }
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close(sockfd);
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}
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freeaddrinfo(res);
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if (rp == NULL) {
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// fprintf(stderr, "Couldn't connect socket\n");
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return false;
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}
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// https://www.man7.org/linux/man-pages/man2/write.2.html
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char *req_msg = "GET / HTTP/1.1\r\n\r\n";
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if (write(sockfd, req_msg, strlen(req_msg)) != strlen(req_msg)) {
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// fprintf(stderr, "Couldn't fully write to socket\n");
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return false;
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}
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// https://www.man7.org/linux/man-pages/man2/recv.2.html
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size_t count = 1000000;
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char buf[count];
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if (recv(sockfd, buf, count-1, MSG_WAITALL) == -1 ) {
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// fprintf(stderr, "Couldn't read from socket\n");
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return false;
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}
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// printf("%s\n", buf);
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close(sockfd);
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return true;
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}
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int main() {
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if (has_internet()) {
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// printf("has internet\n");
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return 0;
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} else {
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// printf("no internet\n");
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return 1;
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}
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}
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