Add col_append_lstr(), speedup column generation for TCP.

When dissecting with columns TCP dissector spends
around 1/4 time in col_append_fstr(), add col_append_lstr()
and do formatting by ourselves.

Change-Id: If90bc26242761884b4991e8db0db62c8f9e32690
Reviewed-on: https://code.wireshark.org/review/2527
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

3 files changed, 63 insertions, 5 deletions

diff --git a/epan/column-utils.c b/epan/column-utils.c
index 401dae865f..f27e4702c4 100644
--- a/epan/column-utils.c
+++ b/epan/column-utils.c
@@ -312,6 +312,45 @@ col_custom_prime_edt(epan_dissect_t *edt, column_info *cinfo)
   }
 }
 
+void
+col_append_lstr(column_info *cinfo, const gint el, const gchar *str, ...)
+{
+  va_list ap;
+  size_t pos, max_len;
+  int    i;
+
+  if (!CHECK_COL(cinfo, el))
+    return;
+
+  if (el == COL_INFO)
+    max_len = COL_MAX_INFO_LEN;
+  else
+    max_len = COL_MAX_LEN;
+
+  for (i = cinfo->col_first[el]; i <= cinfo->col_last[el]; i++) {
+    if (cinfo->fmt_matx[i][el]) {
+      /*
+       * First arrange that we can append, if necessary.
+       */
+      COL_CHECK_APPEND(cinfo, i, max_len);
+
+      pos = strlen(cinfo->col_buf[i]);
+      if (pos >= max_len)
+         return;
+
+      va_start(ap, str);
+      do {
+         if G_UNLIKELY(str == NULL)
+             str = "(null)";
+
+         pos += g_strlcpy(&cinfo->col_buf[i][pos], str, max_len - pos);
+
+      } while (pos < max_len && (str = va_arg(ap, const char *)) != COL_ADD_LSTR_TERMINATOR);
+      va_end(ap);
+    }
+  }
+}
+
 static void
 col_do_append_fstr(column_info *cinfo, const int el, const char *separator, const char *format, va_list ap)
 {
diff --git a/epan/column-utils.h b/epan/column-utils.h
index 3a4587fb90..331bdf517f 100644
--- a/epan/column-utils.h
+++ b/epan/column-utils.h
@@ -269,6 +269,12 @@ gboolean col_based_on_frame_data(column_info *cinfo, const gint col);
  */
 WS_DLL_PUBLIC void	col_append_str(column_info *cinfo, const gint col, const gchar *str);
 
+/* Append the given strings (terminated by COL_ADD_LSTR_TERMINATOR) to a column element,
+ *
+ * Same result as col_append_str() called for every string element.
+ */
+WS_DLL_PUBLIC void	col_append_lstr(column_info *cinfo, const gint el, const gchar *str, ...);
+
 /** Append the given text to a column element, the text will be formatted and copied.
  *
  * Same function as col_append_str() but using a printf-like format string.
diff --git a/epan/dissectors/packet-tcp.c b/epan/dissectors/packet-tcp.c
index a163e680b8..107efa3f62 100644
--- a/epan/dissectors/packet-tcp.c
+++ b/epan/dissectors/packet-tcp.c
@@ -2361,7 +2361,13 @@ tcp_dissect_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 static void
 tcp_info_append_uint(packet_info *pinfo, const char *abbrev, guint32 val)
 {
-    col_append_fstr(pinfo->cinfo, COL_INFO, " %s=%u", abbrev, val);
+    char buf[16];
+
+    guint32_to_str_buf(val, buf, sizeof(buf));
+    /* fstr(" %s=%u", abbrev, val) */
+    col_append_lstr(pinfo->cinfo, COL_INFO,
+        " ", abbrev, "=", buf,
+        COL_ADD_LSTR_TERMINATOR);
 }
 
 static void
@@ -2935,7 +2941,9 @@ dissect_tcpopt_qs(const ip_tcp_opt *optp, tvbuff_t *tvb,
                              "%s: Rate response, %s, TTL diff %u ", optp->name,
                              val_to_str_ext_const(rate, &qs_rate_vals_ext, "Unknown"),
                              tvb_get_guint8(tvb, offset + 3));
-    col_append_fstr(pinfo->cinfo, COL_INFO, " QSresp=%s", val_to_str_ext_const(rate, &qs_rate_vals_ext, "Unknown"));
+    col_append_lstr(pinfo->cinfo, COL_INFO,
+        " QSresp=", val_to_str_ext_const(rate, &qs_rate_vals_ext, "Unknown"),
+        COL_ADD_LSTR_TERMINATOR);
     field_tree = proto_item_add_subtree(tf, ett_tcp_opt_qs);
     proto_tree_add_item(field_tree, hf_tcp_option_kind, tvb,
                         offset, 1, ENC_BIG_ENDIAN);
@@ -3025,8 +3033,10 @@ dissect_tcpopt_scps(const ip_tcp_opt *optp _U_, tvbuff_t *tvb,
                 if (capvector & capvecs[i].mask) {
                     proto_item_append_text(tf, "%s%s", anyflag ? ", " : " (",
                                            capvecs[i].str);
-                    col_append_fstr(pinfo->cinfo, COL_INFO, "%s%s",
-                                    anyflag ? ", " : "", capvecs[i].str);
+                    col_append_lstr(pinfo->cinfo, COL_INFO,
+                                    anyflag ? ", " : "",
+                                    capvecs[i].str,
+                                    COL_ADD_LSTR_TERMINATOR);
                     anyflag = TRUE;
                 }
             }
@@ -4356,7 +4366,10 @@ dissect_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 
     flags_str = tcp_flags_to_str(tcph);
 
-    col_append_fstr(pinfo->cinfo, COL_INFO, " [%s] Seq=%u", flags_str, tcph->th_seq);
+    col_append_lstr(pinfo->cinfo, COL_INFO,
+        " [", flags_str, "]",
+        COL_ADD_LSTR_TERMINATOR);
+    tcp_info_append_uint(pinfo, "Seq", tcph->th_seq);
     if (tcph->th_flags&TH_ACK)
         tcp_info_append_uint(pinfo, "Ack", tcph->th_ack);