Retired the #ifdef DUMP_PACKETS stuff in ssh.c because I'm utterly

sick of recompiling to enable packet dumps. SSH packet dumping is
now provided as a logging option, and dumps to putty.log like all
the other logging options. While I'm at it I cleaned up the format
so that packet types are translated into strings for easy browsing.
POSSIBLE SIDE EFFECT: in the course of this work I had to re-enable
the SSH1 packet length checks which it turns out hadn't actually
been active for some time, so it's possible things might break as a
result. If need be I can always disable those checks for the 0.52
release and think about it more carefully later.

[originally from svn r1493]

logging.c

@@ -0,0 +1,177 @@
+#include <windows.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+#include <time.h>
+#include <assert.h>
+
+#include "putty.h"
+
+/* log session to file stuff ... */
+static FILE *lgfp = NULL;
+static char timdatbuf[20];
+static char currlogfilename[FILENAME_MAX];
+
+static void xlatlognam(char *d, char *s, char *hostname, struct tm *tm);
+
+/*
+ * Log session traffic.
+ */
+void logtraffic(unsigned char c, int logmode)
+{
+    if (cfg.logtype > 0) {
+	if (cfg.logtype == logmode) {
+	    /* deferred open file from pgm start? */
+	    if (!lgfp)
+		logfopen();
+	    if (lgfp)
+		fputc(c, lgfp);
+	}
+    }
+}
+
+/*
+ * Log an SSH packet.
+ */
+void log_packet(int direction, int type, char *texttype, void *data, int len)
+{
+    int i, j, c;
+    char dumpdata[80], smalldata[5];
+
+    if (cfg.logtype != LGTYP_PACKETS)
+	return;
+    if (!lgfp)
+	logfopen();
+    if (lgfp) {
+	fprintf(lgfp, "%s packet type %d / 0x%02x (%s)\n",
+		direction == PKT_INCOMING ? "Incoming" : "Outgoing",
+		type, type, texttype);
+	for (i = 0; i < len; i += 16) {
+	    sprintf(dumpdata, "  %08x%*s\n", i, 1+3*16+2+16, "");
+	    for (j = 0; j < 16 && i+j < len; j++) {
+		int c = ((unsigned char *)data)[i+j];
+		sprintf(smalldata, "%02x", c);
+		dumpdata[10+2+3*j] = smalldata[0];
+		dumpdata[10+2+3*j+1] = smalldata[1];
+		dumpdata[10+1+3*16+2+j] = (isprint(c) ? c : '.');
+	    }
+	    strcpy(dumpdata + 10+1+3*16+2+j, "\n");
+	    fputs(dumpdata, lgfp);
+	}
+    }
+}
+
+/* open log file append/overwrite mode */
+void logfopen(void)
+{
+    char buf[256];
+    time_t t;
+    struct tm tm;
+    char writemod[4];
+
+    if (!cfg.logtype)
+	return;
+    sprintf(writemod, "wb");	       /* default to rewrite */
+
+    time(&t);
+    tm = *localtime(&t);
+
+    /* substitute special codes in file name */
+    xlatlognam(currlogfilename,cfg.logfilename,cfg.host, &tm);
+
+    lgfp = fopen(currlogfilename, "r");	/* file already present? */
+    if (lgfp) {
+	int i;
+	fclose(lgfp);
+	i = askappend(currlogfilename);
+	if (i == 1)
+	    writemod[0] = 'a';	       /* set append mode */
+	else if (i == 0) {	       /* cancelled */
+	    lgfp = NULL;
+	    cfg.logtype = 0;	       /* disable logging */
+	    return;
+	}
+    }
+
+    lgfp = fopen(currlogfilename, writemod);
+    if (lgfp) {			       /* enter into event log */
+	sprintf(buf, "%s session log (%s mode) to file : ",
+		(writemod[0] == 'a') ? "Appending" : "Writing new",
+		(cfg.logtype == LGTYP_ASCII ? "ASCII" :
+		 cfg.logtype == LGTYP_DEBUG ? "raw" : "<ukwn>"));
+	/* Make sure we do not exceed the output buffer size */
+	strncat(buf, currlogfilename, 128);
+	buf[strlen(buf)] = '\0';
+	logevent(buf);
+
+	/* --- write header line into log file */
+	fputs("=~=~=~=~=~=~=~=~=~=~=~= PuTTY log ", lgfp);
+	strftime(buf, 24, "%Y.%m.%d %H:%M:%S", &tm);
+	fputs(buf, lgfp);
+	fputs(" =~=~=~=~=~=~=~=~=~=~=~=\r\n", lgfp);
+    }
+}
+
+void logfclose(void)
+{
+    if (lgfp) {
+	fclose(lgfp);
+	lgfp = NULL;
+    }
+}
+
+/*
+ * translate format codes into time/date strings
+ * and insert them into log file name
+ *
+ * "&Y":YYYY   "&m":MM   "&d":DD   "&T":hhmm   "&h":<hostname>   "&&":&
+ */
+static void xlatlognam(char *d, char *s, char *hostname, struct tm *tm) {
+    char buf[10], *bufp;
+    int size;
+    char *ds = d; /* save start pos. */
+    int len = FILENAME_MAX-1;
+
+    while (*s) {
+	/* Let (bufp, len) be the string to append. */
+	bufp = buf;		       /* don't usually override this */
+	if (*s == '&') {
+	    char c;
+	    s++;
+	    if (*s) switch (c = *s++, tolower(c)) {
+	      case 'y':
+		size = strftime(buf, sizeof(buf), "%Y", tm);
+		break;
+	      case 'm':
+		size = strftime(buf, sizeof(buf), "%m", tm);
+		break;
+	      case 'd':
+		size = strftime(buf, sizeof(buf), "%d", tm);
+		break;
+	      case 't':
+		size = strftime(buf, sizeof(buf), "%H%M%S", tm);
+		break;
+	      case 'h':
+		bufp = hostname;
+		size = strlen(bufp);
+		break;
+	      default:
+		buf[0] = '&';
+		size = 1;
+		if (c != '&')
+		    buf[size++] = c;
+	    }
+	} else {
+	    buf[0] = *s++;
+	    size = 1;
+	}
+	if (size > len)
+	    size = len;
+	memcpy(d, bufp, size);
+	d += size;
+	len -= size;
+    }
+    *d = '\0';
+}