MINOR: peers: Replace hard-coded for peer protocol 64-bits value encoding by macros.

With this patch we define macros for the minimum values which are
encoded for 2 up to 10 bytes. This latter is big enough to encode
UINT64_MAX. We replaced at several places 240 value by PEER_ENC_2BYTES_MIN
which is the minimum value which is encoded with 2 bytes. The peer protocol
encoding consisting in encoding with only one byte a value which is
less than PEER_ENC_2BYTES_MIN and with at least 2 bytes a 64-bits value greater
than PEER_ENC_2BYTES_MIN.
This commit is contained in:
Frdric Lcaille 2019-06-03 18:29:51 +02:00 committed by Willy Tarreau
parent 62b0b0bc02
commit 32b5573b13

View File

@ -172,6 +172,32 @@ struct peer_prep_params {
/* The maximum length of an encoded data length. */
#define PEER_MSG_ENC_LENGTH_MAXLEN 5
/* Minimum 64-bits value encoded with 2 bytes */
#define PEER_ENC_2BYTES_MIN 0xf0 /* 0xf0 (or 240) */
/* 3 bytes */
#define PEER_ENC_3BYTES_MIN ((1ULL << 11) | PEER_ENC_2BYTES_MIN) /* 0x8f0 (or 2288) */
/* 4 bytes */
#define PEER_ENC_4BYTES_MIN ((1ULL << 18) | PEER_ENC_3BYTES_MIN) /* 0x408f0 (or 264432) */
/* 5 bytes */
#define PEER_ENC_5BYTES_MIN ((1ULL << 25) | PEER_ENC_4BYTES_MIN) /* 0x20408f0 (or 33818864) */
/* 6 bytes */
#define PEER_ENC_6BYTES_MIN ((1ULL << 32) | PEER_ENC_5BYTES_MIN) /* 0x1020408f0 (or 4328786160) */
/* 7 bytes */
#define PEER_ENC_7BYTES_MIN ((1ULL << 39) | PEER_ENC_6BYTES_MIN) /* 0x81020408f0 (or 554084600048) */
/* 8 bytes */
#define PEER_ENC_8BYTES_MIN ((1ULL << 46) | PEER_ENC_7BYTES_MIN) /* 0x4081020408f0 (or 70922828777712) */
/* 9 bytes */
#define PEER_ENC_9BYTES_MIN ((1ULL << 53) | PEER_ENC_8BYTES_MIN) /* 0x204081020408f0 (or 9078122083518704) */
/* 10 bytes */
#define PEER_ENC_10BYTES_MIN ((1ULL << 60) | PEER_ENC_9BYTES_MIN) /* 0x10204081020408f0 (or 1161999626690365680) */
/* #7 bit used to detect the last byte to be encoded */
#define PEER_ENC_STOP_BIT 7
/* The byte minimum value with #7 bit set */
#define PEER_ENC_STOP_BYTE (1 << PEER_ENC_STOP_BIT)
/* The left most number of bits set for PEER_ENC_2BYTES_MIN */
#define PEER_ENC_2BYTES_MIN_BITS 4
#define PEER_MSG_HEADER_LEN 2
#define PEER_STKT_CACHE_MAX_ENTRIES 128
@ -260,17 +286,17 @@ int intencode(uint64_t i, char **str) {
unsigned char *msg;
msg = (unsigned char *)*str;
if (i < 240) {
if (i < PEER_ENC_2BYTES_MIN) {
msg[0] = (unsigned char)i;
*str = (char *)&msg[idx+1];
return (idx+1);
}
msg[idx] =(unsigned char)i | 240;
i = (i - 240) >> 4;
while (i >= 128) {
msg[++idx] = (unsigned char)i | 128;
i = (i - 128) >> 7;
msg[idx] =(unsigned char)i | PEER_ENC_2BYTES_MIN;
i = (i - PEER_ENC_2BYTES_MIN) >> PEER_ENC_2BYTES_MIN_BITS;
while (i >= PEER_ENC_STOP_BYTE) {
msg[++idx] = (unsigned char)i | PEER_ENC_STOP_BYTE;
i = (i - PEER_ENC_STOP_BYTE) >> PEER_ENC_STOP_BIT;
}
msg[++idx] = (unsigned char)i;
*str = (char *)&msg[idx+1];
@ -297,14 +323,14 @@ uint64_t intdecode(char **str, char *end)
goto fail;
i = *(msg++);
if (i >= 240) {
shift = 4;
if (i >= PEER_ENC_2BYTES_MIN) {
shift = PEER_ENC_2BYTES_MIN_BITS;
do {
if (msg >= (unsigned char *)end)
goto fail;
i += (uint64_t)*msg << shift;
shift += 7;
} while (*(msg++) >= 128);
shift += PEER_ENC_STOP_BIT;
} while (*(msg++) >= PEER_ENC_STOP_BYTE);
}
*str = (char *)msg;
return i;
@ -1652,7 +1678,7 @@ static inline int peer_recv_msg(struct appctx *appctx, char *msg_head, size_t ms
*totl += reql;
if ((unsigned int)msg_head[2] < 240) {
if ((unsigned int)msg_head[2] < PEER_ENC_2BYTES_MIN) {
*msg_len = msg_head[2];
}
else {