Added error checking to UDP socket creation, at various API levels,

to stop some bad crash bugs. This also makes it possible for NOS
to eventually do the right thing when trying to pick a proper
ephemeral UDP port number. (Not certain that it's totally ready
for that yet).

Orignal dates:
Jan  7 22:59:34 2019 errlst.c
Jan  7 22:58:15 2019 errno.c
Jan  7 22:57:43 2019 errno.h
Jan  7 22:55:04 2019 socket.c
Jan  7 22:55:01 2019 tcpsock.c
Jan  7 23:00:00 2019 udp.c
Jan  7 23:02:40 2019 udpsock.c

errlst.c

@@ -1,7 +1,7 @@
 /* System error list
  *
  * Copyright 1991 Phil Karn, KA9Q
- * Copyright 2017 Jeremy Cooper, KE6JJJ
+ * Copyright 2017, 2019 Jeremy Cooper, KE6JJJ
  */
 #include "top.h"
 
@@ -26,5 +26,6 @@ const char *ksys_errlist[] = {
 	"address in use",               /* 13 - kEADDRINUSE */
 	"bad file descriptor",          /* 14 - kEBADF */
 	"too many files open",          /* 15 - kEMFILE */
-	"bad address"                   /* 16 - kEFAULT */
+	"bad address",                  /* 16 - kEFAULT */
+	"out of memory"                 /* 17 - kENOMEM */
 };

errno.c

@@ -26,6 +26,7 @@ translate_sys_errno(int err)
 	case EBADF: return kEBADF;
 	case EMFILE: return kEMFILE;
 	case EFAULT: return kEFAULT;
+	case ENOMEM: return kENOMEM;
 	default:
 		return kEINVAL;
 	}

errno.h

@@ -23,7 +23,8 @@ extern const char *ksys_errlist[];
 #define	kEBADF		14
 #define	kEMFILE		15
 #define	kEFAULT		16
-#define	kEMAX		16
+#define	kENOMEM		17
+#define	kEMAX		17
 
 /* Translate native error numbers to KA9Q kerrno */
 int translate_sys_errno(int);

socket.c

@@ -205,7 +205,6 @@ int namelen		/* Length of name */
 
 	/* a bind routine is optional - don't fail if it isn't present */
 	if(sp->bind != NULL && (*sp->bind)(up) == -1){
-		kerrno = kEOPNOTSUPP;
 		free(up->name);
 		up->name = NULL;
 		return -1;

udp.c

@@ -1,5 +1,6 @@
 /* Internet User Data Protocol (UDP)
  * Copyright 1991 Phil Karn, KA9Q
+ * Copyright 2019 Jeremy Cooper, KE6JJJ
  */
 #include "top.h"
 
@@ -41,6 +42,10 @@ void (*r_upcall)();
 		return NULL;
 	}
 	up = (struct udp_cb *)callocw(1,sizeof (struct udp_cb));
+	if (up == NULL) {
+		Net_error = NO_MEM;
+		return NULL;
+	}
 	up->socket.address = lsocket->address;
 	up->socket.port = lsocket->port;
 	up->r_upcall = r_upcall;

udpsock.c

@@ -27,7 +27,20 @@ struct usock *up;
 	sp = (struct ksockaddr_in *)up->name;
 	lsock.address = sp->sin_addr.s_addr;
 	lsock.port = sp->sin_port;
-	up->cb.udp = open_udp(&lsock,s_urcall);
+	if ((up->cb.udp = open_udp(&lsock,s_urcall)) == NULL) {
+		switch (Net_error) {
+		case NO_MEM:
+			kerrno = kENOMEM;
+			break;
+		case CON_EXISTS:
+			kerrno = kEADDRINUSE;
+			break;
+		default:
+			kerrno = kEOPNOTSUPP;
+			break;
+		}
+		return -1;
+	}
 	up->cb.udp->user = s;
 	return 0;
 }