Initial commit - currently just a very manual IRC client

1 files changed, 194 insertions, 0 deletions

diff --git a/blabouncer.c b/blabouncer.c
new file mode 100644
index 0000000..679c775
--- /dev/null
+++ b/blabouncer.c
@@ -0,0 +1,194 @@
+// uses socket demo code from https://beej.us/guide/bgnet/html/single/bgnet.html
+// and getstdin() uses getLine() from https://stackoverflow.com/questions/4023895/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <sys/select.h>
+
+#define MAXDATASIZE 513 // max number of bytes we can get at once (RFC2812 says 512, plus one for null terminator)
+#define STDIN 0 // stdin is fd 0
+
+// getstdin() return codes
+#define OK       0
+#define NO_INPUT 1
+#define TOO_LONG 2
+
+// Get stdin line with buffer overrun protection
+static int getstdin(char *prompt, char *buff, size_t sz) {
+  int ch, extra;
+
+  // Print optional prompt
+  if (prompt != NULL) {
+    printf ("%s", prompt);
+    fflush (stdout);
+  }
+
+  // Get the intput from stdin
+  if (fgets (buff, sz, stdin) == NULL) {
+    return NO_INPUT;
+  }
+
+  // If it was too long, there'll be no newline. In that case, we flush
+  // to end of line so that excess doesn't affect the next call.
+  if (buff[strlen(buff)-1] != '\n') { // strlen of the actually entered line, not the original array size
+    extra = 0;
+    while (((ch = getchar()) != '\n') && (ch != EOF)) {
+      extra = 1;
+    }
+    return (extra == 1) ? TOO_LONG : OK;
+  }
+
+  // Otherwise remove newline and give string back to caller.
+  buff[strlen(buff)-1] = '\0';
+  return OK;
+}
+
+// Append CR-LF to the end of a string
+void appendcrlf(char *string) {
+  // Make sure it doesn't already end with CR or LF
+  while (string[strlen(string) - 1] == '\r' || string[strlen(string) - 1] == '\r') {
+    string[strlen(string) - 1] = '\0';
+  }
+
+  int startlen = strlen(string);
+  string[startlen] = '\r';
+  string[startlen + 1] = '\n';
+  string[startlen + 2] = '\0';
+}
+
+// get sockaddr, IPv4 or IPv6:
+void *get_in_addr(struct sockaddr *sa)
+{
+  if (sa->sa_family == AF_INET) {
+    return &(((struct sockaddr_in*)sa)->sin_addr);
+  }
+
+  return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+void dochat(int *sockfd, char *buf) {
+  int numbytes; // Number of bytes received from remote server
+  char outgoingmsg[MAXDATASIZE]; // String to send to server
+  int outgoingmsgrc; // Return code from getstdin() for outgoing message
+
+  fd_set rfds;
+
+  while (1) {
+    FD_ZERO(&rfds); // clear entries from fd set
+
+    FD_SET(STDIN, &rfds); // add STDIN (fd 0) to read fds to monitor
+    FD_SET(*sockfd, &rfds); // add our network socket ''
+
+    if(select(*sockfd + 1, &rfds, NULL, NULL, NULL) < 0) { // network socket + 1, rfds, no writes, no exceptions/errors, no timeout
+      printf("receive error, exiting!?\n");
+      perror("select");
+      // TODO exit here?
+    }
+
+    if(FD_ISSET(*sockfd, &rfds)) {
+      printf("reading socket!\n");
+
+      if ((numbytes = recv(*sockfd, buf, MAXDATASIZE - 1, 0)) == -1) {
+        printf("receive error (-1), exiting...\n");
+        perror("recv");
+        exit(1);
+      } else if (numbytes == 0) {
+        printf("socket closed (or no data received) (0), exiting...\n");
+        perror("recv");
+        exit(1);
+      }
+      buf[numbytes] = '\0';
+
+      printf("RECEIVED: %s\n",buf);
+    }
+
+    if(FD_ISSET(STDIN, &rfds)) {
+      printf("reading stdin!\n");
+
+      outgoingmsgrc = getstdin(NULL, outgoingmsg, sizeof(outgoingmsg));
+
+      if (outgoingmsgrc == NO_INPUT) {
+        printf("\nError!  No input.\n");
+      } else if (outgoingmsgrc == TOO_LONG) {
+        printf ("Error!  Too long.  Would have allowed up to: [%s]\n", outgoingmsg);
+      }
+
+      appendcrlf(outgoingmsg);
+
+      if (send(*sockfd, outgoingmsg, strlen(outgoingmsg), 0) == -1) {
+        printf("send error, exiting...\n");
+        perror("send");
+      }
+    }
+  }
+}
+
+int main(int argc, char *argv[]) {
+  // TODO: see if any of this can be shared (i.e. 1. avoid code duplication, and 2. see if variables can be shared between client/server sockets)
+
+  // I will try to keep to the notion of "server" meaning the real IRCd, "bouncer" meaning the bouncer, and "client" meaning the real IRC client
+
+  // BOUNCER-TO-SERVER socket things
+
+  int sockfd;
+  char buf[MAXDATASIZE];
+  struct addrinfo hints, *servinfo, *p;
+  int rv;
+  char s[INET6_ADDRSTRLEN];
+
+  if (argc != 3) {
+    fprintf(stderr,"usage: %s [hostname] [port]\n", argv[0]);
+    exit(1);
+  }
+
+  memset(&hints, 0, sizeof hints);
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+
+  if ((rv = getaddrinfo(argv[1], argv[2], &hints, &servinfo)) != 0) {
+    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+    return 1;
+  }
+
+  // loop through all the results and connect to the first we can
+  for(p = servinfo; p != NULL; p = p->ai_next) {
+    if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
+      perror("bouncer-server: socket");
+      continue;
+    }
+
+    if (connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+      close(sockfd);
+      perror("bouncer-server: connect");
+      continue;
+    }
+
+    break;
+  }
+
+  if (p == NULL) {
+    fprintf(stderr, "bouncer-server: failed to connect\n");
+    return 2;
+  }
+
+  inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof s);
+  printf("bouncer-server: connecting to %s\n", s);
+
+  freeaddrinfo(servinfo); // all done with this structure
+
+  dochat(&sockfd, buf);
+
+  printf("dochat() complete, closing socket...\n");
+
+  close(sockfd);
+
+  return 0;
+}