68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdio.h>
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/* #include <stdatomic.h>
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#include <time.h>
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#include <pthread.h> */
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#define PORT 6008
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#define BACKLOG 16
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#define RECV_BUF 256
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int main() {
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int server_fd = socket(AF_INET, SOCK_STREAM, 0);
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int opt = 1;
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setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
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struct sockaddr_in addr = {0};
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = INADDR_ANY;
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addr.sin_port = htons(PORT);
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bind(server_fd, (struct sockaddr *)&addr, sizeof(addr));
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listen(server_fd, BACKLOG);
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printf("listening port %d\nbacklog %d\nrecv buffer %d\n", PORT, BACKLOG, RECV_BUF);
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char buf[RECV_BUF];
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const char *hdr = "X-Forwarded-For:";
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const size_t hdrlen = strlen(hdr);
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while(1) {
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int client = accept(server_fd, NULL, NULL);
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if (client < 0) continue;
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ssize_t r = recv(client, buf, sizeof(buf) -1, 0);
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if (r <= 0) { close(client); continue; }
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buf[r] = 0;
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//find header
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char *ip = NULL;
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for (ssize_t i = 0; i < r - (ssize_t)hdrlen; ++i) {
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if (strncasecmp(buf + i, hdr, hdrlen) == 0) {
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ip = buf + i + hdrlen;
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while (*ip == ' ' || *ip == '\t') ip++;
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break;
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}
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}
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//find end
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char *end = ip;
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if (ip) {
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while (*end && *end != '\r' && *end != '\n') end++;
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*end = 0;
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}
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//response
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const char *head = "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nContent-Length: ";
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char lenbuf[32];
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int iplen = ip ? strlen(ip) : 0;
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int len = snprintf(lenbuf, sizeof(lenbuf), "%d\r\n\r\n", iplen);
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send(client, head, strlen(head), 0);
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send(client, lenbuf, len, 0);
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if (iplen > 0) send(client, ip, iplen, 0);
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close(client);
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}
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} |