double
RFC2616_Ttl(const struct sess *sp)
{
double ttl;
unsigned max_age, age;
double h_date, h_expires;
char *p;
const struct http *hp;
hp = sp->wrk->beresp;
assert(sp->wrk->entered != 0.0 && !isnan(sp->wrk->entered));
/* If all else fails, cache using default ttl */
ttl = params->default_ttl;
max_age = age = 0;
h_expires = 0;
h_date = 0;
/*
* Initial cacheability determination per [RFC2616, 13.4]
* We do not support ranges yet, so 206 is out.
*/
switch (sp->err_code) {
default:
sp->wrk->exp.ttl = -1.;
break;
case 200: /* OK */
case 203: /* Non-Authoritative Information */
case 300: /* Multiple Choices */
case 301: /* Moved Permanently */
case 302: /* Moved Temporarily */
case 410: /* Gone */
case 404: /* Not Found */
/*
* First find any relative specification from the backend
* These take precedence according to RFC2616, 13.2.4
*/
if ((http_GetHdrField(hp, H_Cache_Control, "s-maxage", &p) ||
http_GetHdrField(hp, H_Cache_Control, "max-age", &p)) &&
p != NULL) {
if (*p == '-')
max_age = 0;
else
max_age = strtoul(p, NULL, 0);
if (http_GetHdr(hp, H_Age, &p)) {
age = strtoul(p, NULL, 0);
sp->wrk->age = age;
}
if (age > max_age)
ttl = 0;
else
ttl = max_age - age;
break;
}
/* Next look for absolute specifications from backend */
if (http_GetHdr(hp, H_Expires, &p))
h_expires = TIM_parse(p);
/* No expire header, fall back to default */
if (h_expires == 0)
break;
if (http_GetHdr(hp, H_Date, &p))
h_date = TIM_parse(p);
/* If backend told us it is expired already, don't cache. */
if (h_expires < h_date) {
ttl = 0;
break;
}
if (h_date == 0 ||
fabs(h_date - sp->wrk->entered) < params->clock_skew) {
/*
* If we have no Date: header or if it is
* sufficiently close to our clock we will
* trust Expires: relative to our own clock.
*/
if (h_expires < sp->wrk->entered)
ttl = 0;
else
ttl = h_expires - sp->wrk->entered;
break;
} else {
/*
* But even if the clocks are out of whack we can still
* derive a relative time from the two headers.
* (the negative ttl case is caught above)
*/
ttl = (int)(h_expires - h_date);
}
}
/* calculated TTL, Our time, Date, Expires, max-age, age */
WSP(sp, SLT_TTL, "%u RFC %g %.0f %.0f %.0f %u %u", sp->xid,
ttl, sp->wrk->entered, h_date, h_expires, max_age, age);
return (ttl);
}
void
RFC2616_Ttl(struct busyobj *bo)
{
unsigned max_age, age;
double h_date, h_expires;
char *p;
const struct http *hp;
struct exp *expp;
CHECK_OBJ_NOTNULL(bo, BUSYOBJ_MAGIC);
expp = &bo->exp;
hp = bo->beresp;
assert(bo->t_fetch != 0.0 && !isnan(bo->t_fetch));
expp->t_origin = bo->t_fetch;
expp->ttl = cache_param->default_ttl;
expp->grace = cache_param->default_grace;
expp->keep = cache_param->default_keep;
max_age = age = 0;
h_expires = 0;
h_date = 0;
/*
* Initial cacheability determination per [RFC2616, 13.4]
* We do not support ranges yet, so 206 is out.
*/
if (http_GetHdr(hp, H_Age, &p)) {
/*
* We deliberately run with partial results, rather than
* reject the Age: header outright. This will be future
* compatible with fractional seconds.
*/
age = strtoul(p, NULL, 10);
expp->t_origin -= age;
}
if (http_GetHdr(hp, H_Expires, &p))
h_expires = VTIM_parse(p);
if (http_GetHdr(hp, H_Date, &p))
h_date = VTIM_parse(p);
switch (http_GetStatus(hp)) {
default:
expp->ttl = -1.;
break;
case 200: /* OK */
case 203: /* Non-Authoritative Information */
case 300: /* Multiple Choices */
case 301: /* Moved Permanently */
case 302: /* Moved Temporarily */
case 307: /* Temporary Redirect */
case 410: /* Gone */
case 404: /* Not Found */
/*
* First find any relative specification from the backend
* These take precedence according to RFC2616, 13.2.4
*/
if ((http_GetHdrField(hp, H_Cache_Control, "s-maxage", &p) ||
http_GetHdrField(hp, H_Cache_Control, "max-age", &p)) &&
p != NULL) {
if (*p == '-')
max_age = 0;
else
max_age = strtoul(p, NULL, 0);
if (age > max_age)
expp->ttl = 0;
else
expp->ttl = max_age - age;
break;
}
/* No expire header, fall back to default */
if (h_expires == 0)
break;
/* If backend told us it is expired already, don't cache. */
if (h_expires < h_date) {
expp->ttl = 0;
break;
}
if (h_date == 0 ||
fabs(h_date - bo->t_fetch) < cache_param->clock_skew) {
/*
* If we have no Date: header or if it is
* sufficiently close to our clock we will
* trust Expires: relative to our own clock.
*/
if (h_expires < bo->t_fetch)
expp->ttl = 0;
else
expp->ttl = h_expires - bo->t_fetch;
break;
} else {
/*
* But even if the clocks are out of whack we can still
* derive a relative time from the two headers.
* (the negative ttl case is caught above)
*/
expp->ttl = (int)(h_expires - h_date);
}
}
/* calculated TTL, Our time, Date, Expires, max-age, age */
VSLb(bo->vsl, SLT_TTL,
"RFC %.0f %.0f %.0f %.0f %.0f %.0f %.0f %u",
expp->ttl, -1., -1., bo->t_fetch,
expp->t_origin, h_date, h_expires, max_age);
}
void
RFC2616_Ttl(struct busyobj *bo, double now, double *t_origin,
float *ttl, float *grace, float *keep)
{
unsigned max_age, age;
double h_date, h_expires;
const char *p;
const struct http *hp;
CHECK_OBJ_NOTNULL(bo, BUSYOBJ_MAGIC);
assert(now != 0.0 && !isnan(now));
AN(t_origin);
AN(ttl);
AN(grace);
AN(keep);
*t_origin = now;
*ttl = cache_param->default_ttl;
*grace = cache_param->default_grace;
*keep = cache_param->default_keep;
hp = bo->beresp;
max_age = age = 0;
h_expires = 0;
h_date = 0;
/*
* Initial cacheability determination per [RFC2616, 13.4]
* We do not support ranges to the backend yet, so 206 is out.
*/
if (http_GetHdr(hp, H_Age, &p)) {
/*
* We deliberately run with partial results, rather than
* reject the Age: header outright. This will be future
* compatible with fractional seconds.
*/
age = strtoul(p, NULL, 10);
*t_origin -= age;
}
if (http_GetHdr(hp, H_Expires, &p))
h_expires = VTIM_parse(p);
if (http_GetHdr(hp, H_Date, &p))
h_date = VTIM_parse(p);
switch (http_GetStatus(hp)) {
default:
*ttl = -1.;
break;
case 302: /* Moved Temporarily */
case 307: /* Temporary Redirect */
/*
* https://tools.ietf.org/html/rfc7231#section-6.1
*
* Do not apply the default ttl, only set a ttl if Cache-Control
* or Expires are present. Uncacheable otherwise.
*/
*ttl = -1.;
/* FALL-THROUGH */
case 200: /* OK */
case 203: /* Non-Authoritative Information */
case 204: /* No Content */
case 300: /* Multiple Choices */
case 301: /* Moved Permanently */
case 304: /* Not Modified - handled like 200 */
case 404: /* Not Found */
case 410: /* Gone */
case 414: /* Request-URI Too Large */
/*
* First find any relative specification from the backend
* These take precedence according to RFC2616, 13.2.4
*/
if ((http_GetHdrField(hp, H_Cache_Control, "s-maxage", &p) ||
http_GetHdrField(hp, H_Cache_Control, "max-age", &p)) &&
p != NULL) {
if (*p == '-')
max_age = 0;
else
max_age = strtoul(p, NULL, 0);
*ttl = max_age;
break;
}
/* No expire header, fall back to default */
if (h_expires == 0)
break;
/* If backend told us it is expired already, don't cache. */
if (h_expires < h_date) {
*ttl = 0;
break;
}
if (h_date == 0 ||
fabs(h_date - now) < cache_param->clock_skew) {
/*
* If we have no Date: header or if it is
* sufficiently close to our clock we will
* trust Expires: relative to our own clock.
*/
if (h_expires < now)
*ttl = 0;
else
*ttl = h_expires - now;
break;
} else {
/*
* But even if the clocks are out of whack we can still
* derive a relative time from the two headers.
* (the negative ttl case is caught above)
*/
*ttl = (int)(h_expires - h_date);
}
}
/*
* RFC5861 outlines a way to control the use of stale responses.
* We use this to initialize the grace period.
*/
if (*ttl >= 0 && http_GetHdrField(hp, H_Cache_Control,
"stale-while-revalidate", &p) && p != NULL) {
if (*p == '-')
*grace = 0;
else
*grace = strtoul(p, NULL, 0);
}
VSLb(bo->vsl, SLT_TTL,
"RFC %.0f %.0f %.0f %.0f %.0f %.0f %.0f %u",
*ttl, *grace, -1., now,
*t_origin, h_date, h_expires, max_age);
}
