diff options
| -rw-r--r-- | bgpd/bgp_aspath.c | 81 |
1 files changed, 52 insertions, 29 deletions
diff --git a/bgpd/bgp_aspath.c b/bgpd/bgp_aspath.c index 5881abe2..002fff9f 100644 --- a/bgpd/bgp_aspath.c +++ b/bgpd/bgp_aspath.c @@ -389,6 +389,25 @@ aspath_delimiter_char (u_char type, u_char which) return ' '; } +/* countup asns from this segment and index onward */ +static int +assegment_count_asns (struct assegment *seg, int from) +{ + int count = 0; + while (seg) + { + if (!from) + count += seg->length; + else + { + count += (seg->length - from); + from = 0; + } + seg = seg->next; + } + return count; +} + unsigned int aspath_count_confeds (struct aspath *aspath) { @@ -498,21 +517,6 @@ aspath_count_numas (struct aspath *aspath) return num; } -static void -aspath_make_str_big_enough (int len, - char **str_buf, - int *str_size, - int count_to_be_added) -{ -#define TERMINATOR 1 - while (len + count_to_be_added + TERMINATOR > *str_size) - { - *str_size *= 2; - *str_buf = XREALLOC (MTYPE_AS_STR, *str_buf, *str_size); - } -#undef TERMINATOR -} - /* Convert aspath structure to string expression. */ static char * aspath_make_str_count (struct aspath *as) @@ -532,7 +536,18 @@ aspath_make_str_count (struct aspath *as) seg = as->segments; - str_size = ASPATH_STR_DEFAULT_LEN; + /* ASN takes 5 to 10 chars plus seperator, see below. + * If there is one differing segment type, we need an additional + * 2 chars for segment delimiters, and the final '\0'. + * Hopefully this is large enough to avoid hitting the realloc + * code below for most common sequences. + * + * This was changed to 10 after the well-known BGP assertion, which + * had hit some parts of the Internet in May of 2009. + */ +#define ASN_STR_LEN (10 + 1) + str_size = MAX (assegment_count_asns (seg, 0) * ASN_STR_LEN + 2 + 1, + ASPATH_STR_DEFAULT_LEN); str_buf = XMALLOC (MTYPE_AS_STR, str_size); while (seg) @@ -556,24 +571,32 @@ aspath_make_str_count (struct aspath *as) return NULL; } + /* We might need to increase str_buf, particularly if path has + * differing segments types, our initial guesstimate above will + * have been wrong. Need 10 chars for ASN, a seperator each and + * potentially two segment delimiters, plus a space between each + * segment and trailing zero. + * + * This definitely didn't work with the value of 5 bytes and + * 32-bit ASNs. + */ +#define SEGMENT_STR_LEN(X) (((X)->length * ASN_STR_LEN) + 2 + 1 + 1) + if ( (len + SEGMENT_STR_LEN(seg)) > str_size) + { + str_size = len + SEGMENT_STR_LEN(seg); + str_buf = XREALLOC (MTYPE_AS_STR, str_buf, str_size); + } +#undef ASN_STR_LEN +#undef SEGMENT_STR_LEN + if (seg->type != AS_SEQUENCE) - { - aspath_make_str_big_enough (len, &str_buf, &str_size, 1); /* %c */ - len += snprintf (str_buf + len, str_size - len, - "%c", - aspath_delimiter_char (seg->type, AS_SEG_START)); - } + len += snprintf (str_buf + len, str_size - len, + "%c", + aspath_delimiter_char (seg->type, AS_SEG_START)); /* write out the ASNs, with their seperators, bar the last one*/ for (i = 0; i < seg->length; i++) { -#define APPROX_DIG_CNT(x) (x < 100000U ? 5 : 10) - /* %u + %c + %c + " " (last two are below loop) */ - aspath_make_str_big_enough (len, - &str_buf, - &str_size, - APPROX_DIG_CNT(seg->as[i]) + 1 + 1 + 1); - len += snprintf (str_buf + len, str_size - len, "%u", seg->as[i]); if (i < (seg->length - 1)) |