1 files changed, 115 insertions, 0 deletions
diff --git a/pgm4/inet_dgrams.d/recv_udp.c b/pgm4/inet_dgrams.d/recv_udp.c
new file mode 100644
index 0000000..24c47b5
--- /dev/null
+++ b/pgm4/inet_dgrams.d/recv_udp.c
@@ -0,0 +1,115 @@
+/*********************************************************************\
+* 			  RECV_UDP.C				      *
+* Test of UDP/IP. Receive datagrams on internet socket bound to port  *
+* 0x3333 on the local host.					      *
+* 								      *
+* To use:							      *
+* 	1) On the appropriate host, invoke this code by		      *
+* 	   "recv_udp&".						      *
+* 	2) Invoke send_udp as many times as desired on the	      *
+* 	   remote host.						      *
+* 	3) When done, MAKE SURE TO KILL THIS BACKGROUND PROCESS!      *
+* 								      *
+* Phil Kearns							      *
+* April 11, 1987		 				      *
+* 								      *
+* Modified February 2009: use getaddrinfo()                           *
+\*********************************************************************/
+
+#include        <stdlib.h>
+#include	<signal.h>
+#include	<errno.h>
+#include	<string.h>
+#include	<stdio.h>
+#include	<sys/types.h>
+#include	<sys/socket.h>
+#include	<netinet/in.h>
+#include	<netdb.h>
+#include        <arpa/inet.h>
+
+void printsin(struct sockaddr_in*, char*, char*);
+
+int main()
+{
+    int	socket_fd, cc, ecode;
+    socklen_t fsize;
+    struct sockaddr_in	*s_in, from;
+    struct addrinfo hints, *addrlist;
+    void printsin();
+
+    struct {
+	char	head;
+	u_long	body;
+	char	tail;
+    } msg;
+
+/*
+   In order to attach a name to the socket created above, first fill
+   in the appropriate blanks in an inet socket address data structure
+   called "s_in". We blindly pick port number 0x3333. The second step
+   is to BIND the address to the socket. If port 0x3333 is in use, the
+   bind system call will fail detectably.
+*/
+
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_INET; hints.ai_socktype = SOCK_DGRAM;
+  hints.ai_flags = AI_NUMERICSERV | AI_PASSIVE; hints.ai_protocol = 0;
+  hints.ai_canonname = NULL; hints.ai_addr = NULL;
+  hints.ai_next = NULL;
+
+/*
+ getaddrinfo() should return a single result, denoting
+ a SOCK_DGRAM socket on any interface of this system at
+ port 0x3333.
+*/
+
+  ecode = getaddrinfo(NULL, "13107", &hints, &addrlist);
+  if (ecode != 0) {
+    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ecode));
+    exit(1);
+  }
+
+  s_in = (struct sockaddr_in *) addrlist->ai_addr;
+
+  printsin(s_in, "RECV_UDP", "Local socket is:"); fflush(stdout);
+
+/*
+   Create the socket to be used for datagram reception. Initially,
+   it has no name in the internet (or any other) domain.
+*/
+  socket_fd = socket (addrlist->ai_family, addrlist->ai_socktype, 0);
+  if (socket_fd < 0) {
+    perror ("recv_udp:socket");
+    exit (1);
+  }
+
+/*
+   bind port 0x3333 on the current host to the socket accessed through
+   socket_fd. If port in use, bind() will fail and we die.
+*/
+
+  if (bind(socket_fd, (struct sockaddr *)s_in, sizeof(struct sockaddr_in)) < 0) {
+    perror("recv_udp:bind");
+    exit(1);
+  }
+
+  for(;;) {
+    fsize = sizeof(from);
+    cc = recvfrom(socket_fd, &msg, sizeof(msg), 0, (struct sockaddr *)&from, &fsize);
+    if (cc < 0) perror("recv_udp:recvfrom");
+    printsin( &from, "recv_udp: ", "Packet from:");
+    printf("Got data ::%c%u%c\n",msg.head,ntohl(msg.body),msg.tail);
+    fflush(stdout);
+  }
+  exit(0);
+}
+
+void printsin(struct sockaddr_in *sin, char *m1, char *m2 )
+{
+  char fromip[INET_ADDRSTRLEN];
+
+  printf ("%s %s:\n", m1, m2);
+  printf ("  family %d, addr %s, port %d\n", sin -> sin_family,
+	    inet_ntop(AF_INET, &(sin->sin_addr.s_addr), fromip, sizeof(fromip)),
+            ntohs((unsigned short)(sin -> sin_port)));
+}