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r15750@tombo: nickm | 2007-12-29 19:12:51 -0500

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Make HTTP-processing code in buffers.c faster: do not pull up 50K of text into the first chunk if the headers end earlier than that.


svn:r13006
This commit is contained in:
Nick Mathewson 2007-12-30 00:13:07 +00:00
parent cd85eac0d3
commit 46a27c2f93
1 changed files with 36 additions and 57 deletions
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93
src/or/buffers.c
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@ -943,28 +943,32 @@ move_buf_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen)
return cp;
}
// #define BUFPOS
#ifdef BUFPOS
/** Internal structure: represents a position in a buffer. */
typedef struct buf_pos_t {
chunk_t *chunk;
int pos;
int pos_absolute;
};
const chunk_t *chunk; /**< Which chunk are we pointing to? */
int pos; /**< Which character inside the chunk's data are we pointing to? */
int pos_absolute; /**< Which character inside the buffer are we pointing to?
*/
} buf_pos_t;
/** Initialize <b>out</b> to point to the first character of <b>buf</b>.*/
static void
buf_pos_init(buf_t *buf, buf_pos_t *out)
buf_pos_init(const buf_t *buf, buf_pos_t *out)
{
out->chunk = buf->head;
out->pos = 0;
out->pos_absolute = 0;
}
/** Advance <b>out</b> to the first appearance of <b>ch</b> at the current
* position of <b>out</b>, or later. Return -1 if no instances are found;
* otherwise returns the absolute position of the character. */
static int
buf_find_pos_of_char(const buf_t *buf, char ch, buf_pos_t *out)
buf_find_pos_of_char(char ch, buf_pos_t *out)
{
chunk_t *chunk;
const chunk_t *chunk;
int offset = 0;
int pos = chunk->pos;
int pos = out->pos;
for (chunk = out->chunk; chunk; chunk = chunk->next) {
char *cp = memchr(chunk->data+pos, ch, chunk->datalen-pos);
if (cp) {
@ -980,10 +984,12 @@ buf_find_pos_of_char(const buf_t *buf, char ch, buf_pos_t *out)
return -1;
}
/** Advance <b>pos</b> by a single character, if there are any more characters
* in the buffer. Returns 0 on sucess, -1 on failure. */
static INLINE int
buf_pos_inc(buf_pos_t *pos)
{
if (pos->pos == pos->chunk->datalen) {
if ((size_t)pos->pos == pos->chunk->datalen) {
if (!pos->chunk->next)
return -1;
pos->chunk = pos->chunk->next;
@ -992,43 +998,46 @@ buf_pos_inc(buf_pos_t *pos)
++pos->pos;
}
++pos->pos_absolute;
return 0;
}
/** Return true iff the <b>n</b>-character string in <b>s</b> appears
* (verbatim) at <b>pos</b>. */
static int
buf_matches_at_pos(const buf_t *buf, const buf_pos_t *pos, const char *s,
int n)
buf_matches_at_pos(const buf_pos_t *pos, const char *s, int n)
{
buf_pos_t p;
memcpy(p, pos, sizeof(p));
memcpy(&p, pos, sizeof(p));
while (n) {
char ch = p->chunk->data[p->pos];
char ch = p.chunk->data[p.pos];
if (ch != *s)
return 0;
++s;
--n;
if (buf_pos_inc(p)<0)
if (buf_pos_inc(&p)<0)
return 0;
}
return 1;
}
/** Return the first position in <b>buf</b> at which the <b>n</b>-character
* string <b>s</b> occurs, or -1 if it does not occur. */
static int
buf_find_string_offset(const char *buf, const char *s, int n)
buf_find_string_offset(const buf_t *buf, const char *s, int n)
{
buf_pos_t pos;
buf_pos_init(buf, &pos);
while (buf_find_pos_of_char(buf, *s, &pos) >= 0) {
if (buf_matches_at_pos(buf, pos, s, n)) {
return pos->pos_absolute;
while (buf_find_pos_of_char(*s, &pos) >= 0) {
if (buf_matches_at_pos(&pos, s, n)) {
return pos.pos_absolute;
} else {
if (buf_pos_inc(pos)<0)
if (buf_pos_inc(&pos)<0)
return -1;
}
}
return -1;
}
#endif
/** There is a (possibly incomplete) http statement on <b>buf</b>, of the
* form "\%s\\r\\n\\r\\n\%s", headers, body. (body may contain nuls.)
@ -1055,21 +1064,17 @@ fetch_from_buf_http(buf_t *buf,
char **body_out, size_t *body_used, size_t max_bodylen,
int force_complete)
{
char *headers, *p, *body;
char *headers, *p;
size_t headerlen, bodylen, contentlen;
#ifdef BUFPOS
int crlf_offset;
#endif
check();
if (!buf->head)
return 0;
headers = buf->head->data;
#ifdef BUFPOS
crlf_offset = buf_find_string_offset(buf, "\r\n\r\n", 4);
if (crlf_offset > max_headerlen ||
if (crlf_offset > (int)max_headerlen ||
(crlf_offset < 0 && buf->datalen > max_headerlen)) {
log_debug(LD_HTTP,"headers too long.");
return -1;
@ -1077,37 +1082,11 @@ fetch_from_buf_http(buf_t *buf,
log_debug(LD_HTTP,"headers not all here yet.");
return 0;
}
if (buf->head->datalen < crlf_offset + 4)
/* Okay, we have a full header. Make sure it all appears in the first
* chunk. */
if ((int)buf->head->datalen < crlf_offset + 4)
buf_pullup(buf, crlf_offset+4, 0);
headerlen = crlf_offset + 4;
body = buf->data + headerlen; /*XXX020 unused. */
#else
/* See if CRLFCRLF is already in the head chunk. If it is, we don't need
* to move or resize anything. */
body = (char*) tor_memmem(buf->head->data, buf->head->datalen,
"\r\n\r\n", 4);
if (!body && buf->datalen > buf->head->datalen) {
size_t len_scanned = buf->head->datalen;
buf_pullup(buf, max_headerlen, 0);
headers = buf->head->data;
/* avoid searching the original part of the head chunk twice. */
len_scanned = (len_scanned > 4) ? len_scanned - 4 : 0;
body = (char*) tor_memmem(buf->head->data + len_scanned,
buf->head->datalen - len_scanned,
"\r\n\r\n", 4);
}
if (!body) {
if (buf->head->datalen >= max_headerlen) {
log_debug(LD_HTTP,"headers too long.");
return -1;
}
log_debug(LD_HTTP,"headers not all here yet.");
return 0;
}
body += 4; /* Skip the the CRLFCRLF */
headerlen = body-headers; /* includes the CRLFCRLF */
#endif
bodylen = buf->datalen - headerlen;
log_debug(LD_HTTP,"headerlen %d, bodylen %d.", (int)headerlen, (int)bodylen);