util: truncmsg: New way of manipulating buffers

[secnet.git] / util.h

diff --git a/util.h b/util.h
index 3549eb0fa251853c28f5c3aac1cdcd184c9ce180..d783cd076b10c7a70ecd7b215ba2947d61913d08 100644 (file)
--- a/util.h
+++ b/util.h
@@ -1,3 +1,22 @@
+/*
+ * This file is part of secnet.
+ * See README for full list of copyright holders.
+ *
+ * secnet is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * secnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 3 along with secnet; if not, see
+ * https://www.gnu.org/licenses/gpl.html.
+ */
+
 #ifndef util_h
 #define util_h
 
@@ -30,6 +49,16 @@ extern void *buf_prepend(struct buffer_if *buf, int32_t amount);
 extern void *buf_unappend(struct buffer_if *buf, int32_t amount);
 extern void *buf_unprepend(struct buffer_if *buf, int32_t amount);
 
+/* These construct a message in a buffer, truncating if necessary.
+ * _string is only safe for trusted input and *not* UTF-8 (sorry).
+ * _packet_string is safe for any input, including untrusted.
+ * _terminate arranges for the buffer to be null-terminated (and
+ * maybe for a trailing `...' to indicate truncation), and returns
+ * a pointer to the null-terminated string. */
+void truncmsg_add_string(struct buffer_if *buf, cstring_t s);
+void truncmsg_add_packet_string(struct buffer_if*, int32_t, const uint8_t*);
+const char *truncmsg_terminate(const struct buffer_if *buf);
+
 /*
  * void BUF_ADD_BYTES(append,    struct buffer_if*, const void*, int32_t size);
  * void BUF_ADD_BYTES(prepend,   struct buffer_if*, const void*, int32_t size);
@@ -67,12 +96,35 @@ extern void buffer_readonly_clone(struct buffer_if *n, const struct buffer_if*);
    * it must NOT be freed. */
 
 extern void buf_append_string(struct buffer_if *buf, cstring_t s);
+  /* Append a two-byte length and the string to the buffer. Length is in
+   * network byte order. */
+
+static inline int hex_encode_size(int binsize) { return binsize*2 + 1; }
+extern void hex_encode(const uint8_t *bin, int binsize, char *buf);
+  /* Convert a byte array to hex into a supplied buffer. */
+extern string_t hex_encode_alloc(const uint8_t *bin, int binsize);
+  /* Returns the result in a freshly allocated string. */
+
+extern bool_t hex_decode(uint8_t *buffer, int32_t buflen, int32_t *outlen,
+                        cstring_t hb, bool_t allow_odd_nibble);
+  /* Convert a hex string to binary, storing the result in buffer.  If
+   * allow_odd_nibble then it is acceptable if the input is an odd number of
+   * digits, and an additional leading zero digit is assumed; otherwise, this
+   * is not acceptable and the conversion fails.
+   *
+   * The input is processed left to right until it is consumed, the buffer is
+   * full, or an error is encountered in the input.  The length of output
+   * produced is stored in *outlen.  Returns true if the entire input was
+   * processed without error; otherwise false. */
 
 extern void read_mpbin(MP_INT *a, uint8_t *bin, int binsize);
+  /* Convert a buffer into its MP_INT representation */
 
 extern char *write_mpstring(MP_INT *a);
+  /* Convert a MP_INT into a hex string */
 
 extern int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen);
+  /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 
 extern struct log_if *init_log(list_t *loglist);
 
@@ -82,6 +134,9 @@ extern void send_nak(const struct comm_addr *dest, uint32_t our_index,
 
 extern int consttime_memeq(const void *s1, const void *s2, size_t n);
 
+void hash_hash(const struct hash_if *hashi, const void *msg, int32_t len,
+              uint8_t *digest /* hi->hlen bytes */);
+
 const char *iaddr_to_string(const union iaddr *ia);
 int iaddr_socklen(const union iaddr *ia);
 
@@ -89,6 +144,21 @@ void string_item_to_iaddr(const item_t *item, uint16_t port, union iaddr *ia,
                          const char *desc);
 
 
+/*
+ * SBUF_DEFINE(int nbufs, size_t size);
+ *   // Generates a number of definitions and statements organising
+ *   // nbufs rotating char[size] buffers such that subsequent code
+ *   // may refer to:
+ * char *const SBUF;
+ */
+#define SBUF_DEFINE(nbufs, size)                       \
+    static int static_bufs__bufnum;                    \
+    static char static_bufs__bufs[(nbufs)][(size)];    \
+    static_bufs__bufnum++;                             \
+    static_bufs__bufnum %= (nbufs);                    \
+    static_bufs__bufs[static_bufs__bufnum]
+#define SBUF (static_bufs__bufs[static_bufs__bufnum])
+
 /*----- line-buffered asynch input -----*/
 
 enum async_linebuf_result {
@@ -98,6 +168,8 @@ enum async_linebuf_result {
     async_linebuf_broken,
 };
 
+const char *pollbadbit(int revents); /* returns 0, or bad bit description */
+
 enum async_linebuf_result
 async_linebuf_read(struct pollfd *pfd, struct buffer_if *buf,
                   const char **emsg_out);