Reworked multi headers to use linked lists.

Multi headers are now using linked lists instead of arrays.  Notably,
the following fields were changed: r->headers_in.cookies (renamed
to r->headers_in.cookie), r->headers_in.x_forwarded_for,
r->headers_out.cache_control, r->headers_out.link, u->headers_in.cache_control
u->headers_in.cookies (renamed to u->headers_in.set_cookie).

The r->headers_in.cookies and u->headers_in.cookies fields were renamed
to r->headers_in.cookie and u->headers_in.set_cookie to match header names.

The ngx_http_parse_multi_header_lines() and ngx_http_parse_set_cookie_lines()
functions were changed accordingly.

With this change, multi headers are now essentially equivalent to normal
headers, and following changes will further make them equivalent.

17 files changed, 175 insertions, 245 deletions

diff --git a/src/http/modules/ngx_http_geo_module.c b/src/http/modules/ngx_http_geo_module.c
index 153b6aaf3..ef4e9b84a 100644
--- a/src/http/modules/ngx_http_geo_module.c
+++ b/src/http/modules/ngx_http_geo_module.c
@@ -327,15 +327,15 @@ static ngx_int_t
 ngx_http_geo_addr(ngx_http_request_t *r, ngx_http_geo_ctx_t *ctx,
     ngx_addr_t *addr)
 {
-    ngx_array_t  *xfwd;
+    ngx_table_elt_t  *xfwd;
 
     if (ngx_http_geo_real_addr(r, ctx, addr) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    xfwd = &r->headers_in.x_forwarded_for;
+    xfwd = r->headers_in.x_forwarded_for;
 
-    if (xfwd->nelts > 0 && ctx->proxies != NULL) {
+    if (xfwd != NULL && ctx->proxies != NULL) {
         (void) ngx_http_get_forwarded_addr(r, addr, xfwd, NULL,
                                            ctx->proxies, ctx->proxy_recursive);
     }
diff --git a/src/http/modules/ngx_http_geoip_module.c b/src/http/modules/ngx_http_geoip_module.c
index 5ea4f5fb0..eaf98764f 100644
--- a/src/http/modules/ngx_http_geoip_module.c
+++ b/src/http/modules/ngx_http_geoip_module.c
@@ -240,16 +240,16 @@ static u_long
 ngx_http_geoip_addr(ngx_http_request_t *r, ngx_http_geoip_conf_t *gcf)
 {
     ngx_addr_t           addr;
-    ngx_array_t         *xfwd;
+    ngx_table_elt_t     *xfwd;
     struct sockaddr_in  *sin;
 
     addr.sockaddr = r->connection->sockaddr;
     addr.socklen = r->connection->socklen;
     /* addr.name = r->connection->addr_text; */
 
-    xfwd = &r->headers_in.x_forwarded_for;
+    xfwd = r->headers_in.x_forwarded_for;
 
-    if (xfwd->nelts > 0 && gcf->proxies != NULL) {
+    if (xfwd != NULL && gcf->proxies != NULL) {
         (void) ngx_http_get_forwarded_addr(r, &addr, xfwd, NULL,
                                            gcf->proxies, gcf->proxy_recursive);
     }
@@ -292,7 +292,7 @@ static geoipv6_t
 ngx_http_geoip_addr_v6(ngx_http_request_t *r, ngx_http_geoip_conf_t *gcf)
 {
     ngx_addr_t            addr;
-    ngx_array_t          *xfwd;
+    ngx_table_elt_t      *xfwd;
     in_addr_t             addr4;
     struct in6_addr       addr6;
     struct sockaddr_in   *sin;
@@ -302,9 +302,9 @@ ngx_http_geoip_addr_v6(ngx_http_request_t *r, ngx_http_geoip_conf_t *gcf)
     addr.socklen = r->connection->socklen;
     /* addr.name = r->connection->addr_text; */
 
-    xfwd = &r->headers_in.x_forwarded_for;
+    xfwd = r->headers_in.x_forwarded_for;
 
-    if (xfwd->nelts > 0 && gcf->proxies != NULL) {
+    if (xfwd != NULL && gcf->proxies != NULL) {
         (void) ngx_http_get_forwarded_addr(r, &addr, xfwd, NULL,
                                            gcf->proxies, gcf->proxy_recursive);
     }
diff --git a/src/http/modules/ngx_http_headers_filter_module.c b/src/http/modules/ngx_http_headers_filter_module.c
index a4c8cc264..995beb41b 100644
--- a/src/http/modules/ngx_http_headers_filter_module.c
+++ b/src/http/modules/ngx_http_headers_filter_module.c
@@ -329,8 +329,7 @@ ngx_http_set_expires(ngx_http_request_t *r, ngx_http_headers_conf_t *conf)
     time_t               now, expires_time, max_age;
     ngx_str_t            value;
     ngx_int_t            rc;
-    ngx_uint_t           i;
-    ngx_table_elt_t     *e, *cc, **ccp;
+    ngx_table_elt_t     *e, *cc;
     ngx_http_expires_t   expires;
 
     expires = conf->expires;
@@ -371,38 +370,28 @@ ngx_http_set_expires(ngx_http_request_t *r, ngx_http_headers_conf_t *conf)
     len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT");
     e->value.len = len - 1;
 
-    ccp = r->headers_out.cache_control.elts;
+    cc = r->headers_out.cache_control;
 
-    if (ccp == NULL) {
-
-        if (ngx_array_init(&r->headers_out.cache_control, r->pool,
-                           1, sizeof(ngx_table_elt_t *))
-            != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
+    if (cc == NULL) {
 
         cc = ngx_list_push(&r->headers_out.headers);
         if (cc == NULL) {
             return NGX_ERROR;
         }
 
+        r->headers_out.cache_control = cc;
+        cc->next = NULL;
+
         cc->hash = 1;
         ngx_str_set(&cc->key, "Cache-Control");
 
-        ccp = ngx_array_push(&r->headers_out.cache_control);
-        if (ccp == NULL) {
-            return NGX_ERROR;
-        }
-
-        *ccp = cc;
-
     } else {
-        for (i = 1; i < r->headers_out.cache_control.nelts; i++) {
-            ccp[i]->hash = 0;
+        for (cc = cc->next; cc; cc = cc->next) {
+            cc->hash = 0;
         }
 
-        cc = ccp[0];
+        cc = r->headers_out.cache_control;
+        cc->next = NULL;
     }
 
     if (expires == NGX_HTTP_EXPIRES_EPOCH) {
@@ -564,22 +553,12 @@ static ngx_int_t
 ngx_http_add_multi_header_lines(ngx_http_request_t *r,
     ngx_http_header_val_t *hv, ngx_str_t *value)
 {
-    ngx_array_t      *pa;
     ngx_table_elt_t  *h, **ph;
 
     if (value->len == 0) {
         return NGX_OK;
     }
 
-    pa = (ngx_array_t *) ((char *) &r->headers_out + hv->offset);
-
-    if (pa->elts == NULL) {
-        if (ngx_array_init(pa, r->pool, 1, sizeof(ngx_table_elt_t *)) != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
-    }
-
     h = ngx_list_push(&r->headers_out.headers);
     if (h == NULL) {
         return NGX_ERROR;
@@ -589,12 +568,12 @@ ngx_http_add_multi_header_lines(ngx_http_request_t *r,
     h->key = hv->key;
     h->value = *value;
 
-    ph = ngx_array_push(pa);
-    if (ph == NULL) {
-        return NGX_ERROR;
-    }
+    ph = (ngx_table_elt_t **) ((char *) &r->headers_out + hv->offset);
+
+    while (*ph) { ph = &(*ph)->next; }
 
     *ph = h;
+    h->next = NULL;
 
     return NGX_OK;
 }
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 7c4061c02..644dacd51 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -2559,22 +2559,20 @@ static ngx_int_t
 ngx_http_proxy_add_x_forwarded_for_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
 {
-    size_t             len;
-    u_char            *p;
-    ngx_uint_t         i, n;
-    ngx_table_elt_t  **h;
+    size_t            len;
+    u_char           *p;
+    ngx_table_elt_t  *h, *xfwd;
 
     v->valid = 1;
     v->no_cacheable = 0;
     v->not_found = 0;
 
-    n = r->headers_in.x_forwarded_for.nelts;
-    h = r->headers_in.x_forwarded_for.elts;
+    xfwd = r->headers_in.x_forwarded_for;
 
     len = 0;
 
-    for (i = 0; i < n; i++) {
-        len += h[i]->value.len + sizeof(", ") - 1;
+    for (h = xfwd; h; h = h->next) {
+        len += h->value.len + sizeof(", ") - 1;
     }
 
     if (len == 0) {
@@ -2593,8 +2591,8 @@ ngx_http_proxy_add_x_forwarded_for_variable(ngx_http_request_t *r,
     v->len = len;
     v->data = p;
 
-    for (i = 0; i < n; i++) {
-        p = ngx_copy(p, h[i]->value.data, h[i]->value.len);
+    for (h = xfwd; h; h = h->next) {
+        p = ngx_copy(p, h->value.data, h->value.len);
         *p++ = ','; *p++ = ' ';
     }
 
diff --git a/src/http/modules/ngx_http_realip_module.c b/src/http/modules/ngx_http_realip_module.c
index 9586ebe07..f6731e780 100644
--- a/src/http/modules/ngx_http_realip_module.c
+++ b/src/http/modules/ngx_http_realip_module.c
@@ -134,9 +134,8 @@ ngx_http_realip_handler(ngx_http_request_t *r)
     ngx_str_t                   *value;
     ngx_uint_t                   i, hash;
     ngx_addr_t                   addr;
-    ngx_array_t                 *xfwd;
     ngx_list_part_t             *part;
-    ngx_table_elt_t             *header;
+    ngx_table_elt_t             *header, *xfwd;
     ngx_connection_t            *c;
     ngx_http_realip_ctx_t       *ctx;
     ngx_http_realip_loc_conf_t  *rlcf;
@@ -168,9 +167,9 @@ ngx_http_realip_handler(ngx_http_request_t *r)
 
     case NGX_HTTP_REALIP_XFWD:
 
-        xfwd = &r->headers_in.x_forwarded_for;
+        xfwd = r->headers_in.x_forwarded_for;
 
-        if (xfwd->elts == NULL) {
+        if (xfwd == NULL) {
             return NGX_DECLINED;
         }
 
diff --git a/src/http/modules/ngx_http_userid_filter_module.c b/src/http/modules/ngx_http_userid_filter_module.c
index 1e33c5c96..e52844446 100644
--- a/src/http/modules/ngx_http_userid_filter_module.c
+++ b/src/http/modules/ngx_http_userid_filter_module.c
@@ -319,10 +319,9 @@ ngx_http_userid_set_variable(ngx_http_request_t *r,
 static ngx_http_userid_ctx_t *
 ngx_http_userid_get_uid(ngx_http_request_t *r, ngx_http_userid_conf_t *conf)
 {
-    ngx_int_t                n;
-    ngx_str_t                src, dst;
-    ngx_table_elt_t        **cookies;
-    ngx_http_userid_ctx_t   *ctx;
+    ngx_str_t               src, dst;
+    ngx_table_elt_t        *cookie;
+    ngx_http_userid_ctx_t  *ctx;
 
     ctx = ngx_http_get_module_ctx(r, ngx_http_userid_filter_module);
 
@@ -339,9 +338,9 @@ ngx_http_userid_get_uid(ngx_http_request_t *r, ngx_http_userid_conf_t *conf)
         ngx_http_set_ctx(r, ctx, ngx_http_userid_filter_module);
     }
 
-    n = ngx_http_parse_multi_header_lines(&r->headers_in.cookies, &conf->name,
-                                          &ctx->cookie);
-    if (n == NGX_DECLINED) {
+    cookie = ngx_http_parse_multi_header_lines(r, r->headers_in.cookie,
+                                               &conf->name, &ctx->cookie);
+    if (cookie == NULL) {
         return ctx;
     }
 
@@ -349,10 +348,9 @@ ngx_http_userid_get_uid(ngx_http_request_t *r, ngx_http_userid_conf_t *conf)
                    "uid cookie: \"%V\"", &ctx->cookie);
 
     if (ctx->cookie.len < 22) {
-        cookies = r->headers_in.cookies.elts;
         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                       "client sent too short userid cookie \"%V\"",
-                      &cookies[n]->value);
+                      &cookie->value);
         return ctx;
     }
 
@@ -370,10 +368,9 @@ ngx_http_userid_get_uid(ngx_http_request_t *r, ngx_http_userid_conf_t *conf)
     dst.data = (u_char *) ctx->uid_got;
 
     if (ngx_decode_base64(&dst, &src) == NGX_ERROR) {
-        cookies = r->headers_in.cookies.elts;
         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                       "client sent invalid userid cookie \"%V\"",
-                      &cookies[n]->value);
+                      &cookie->value);
         return ctx;
     }
 
diff --git a/src/http/modules/perl/nginx.xs b/src/http/modules/perl/nginx.xs
index caf7c084a..e2180e6cf 100644
--- a/src/http/modules/perl/nginx.xs
+++ b/src/http/modules/perl/nginx.xs
@@ -302,7 +302,7 @@ header_in(r, key)
 
     if (hh) {
 
-        if (hh->offset == offsetof(ngx_http_headers_in_t, cookies)) {
+        if (hh->offset == offsetof(ngx_http_headers_in_t, cookie)) {
             sep = ';';
             goto multi;
         }
@@ -327,17 +327,13 @@ header_in(r, key)
 
         /* Cookie, X-Forwarded-For */
 
-        a = (ngx_array_t *) ((char *) &r->headers_in + hh->offset);
-
-        n = a->nelts;
+        ph = (ngx_table_elt_t **) ((char *) &r->headers_in + hh->offset);
 
-        if (n == 0) {
+        if (*ph == NULL) {
             XSRETURN_UNDEF;
         }
 
-        ph = a->elts;
-
-        if (n == 1) {
+        if ((*ph)->next == NULL) {
             ngx_http_perl_set_targ((*ph)->value.data, (*ph)->value.len);
 
             goto done;
@@ -345,8 +341,8 @@ header_in(r, key)
 
         size = - (ssize_t) (sizeof("; ") - 1);
 
-        for (i = 0; i < n; i++) {
-            size += ph[i]->value.len + sizeof("; ") - 1;
+        for (h = *ph; h; h = h->next) {
+            size += h->value.len + sizeof("; ") - 1;
         }
 
         value = ngx_pnalloc(r->pool, size);
@@ -357,10 +353,10 @@ header_in(r, key)
 
         p = value;
 
-        for (i = 0; /* void */ ; i++) {
-            p = ngx_copy(p, ph[i]->value.data, ph[i]->value.len);
+        for (h = *ph; h; h = h->next) {
+            p = ngx_copy(p, h->value.data, h->value.len);
 
-            if (i == n - 1) {
+            if (h->next == NULL) {
                 break;
             }
 
diff --git a/src/http/ngx_http.h b/src/http/ngx_http.h
index be8b7cd71..a7f312f41 100644
--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -103,10 +103,10 @@ ngx_int_t ngx_http_parse_unsafe_uri(ngx_http_request_t *r, ngx_str_t *uri,
     ngx_str_t *args, ngx_uint_t *flags);
 ngx_int_t ngx_http_parse_header_line(ngx_http_request_t *r, ngx_buf_t *b,
     ngx_uint_t allow_underscores);
-ngx_int_t ngx_http_parse_multi_header_lines(ngx_array_t *headers,
-    ngx_str_t *name, ngx_str_t *value);
-ngx_int_t ngx_http_parse_set_cookie_lines(ngx_array_t *headers,
-    ngx_str_t *name, ngx_str_t *value);
+ngx_table_elt_t *ngx_http_parse_multi_header_lines(ngx_http_request_t *r,
+    ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value);
+ngx_table_elt_t *ngx_http_parse_set_cookie_lines(ngx_http_request_t *r,
+    ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value);
 ngx_int_t ngx_http_arg(ngx_http_request_t *r, u_char *name, size_t len,
     ngx_str_t *value);
 void ngx_http_split_args(ngx_http_request_t *r, ngx_str_t *uri,
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index ad8caad19..afb086284 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2024,8 +2024,7 @@ ngx_http_gzip_ok(ngx_http_request_t *r)
 {
     time_t                     date, expires;
     ngx_uint_t                 p;
-    ngx_array_t               *cc;
-    ngx_table_elt_t           *e, *d, *ae;
+    ngx_table_elt_t           *e, *d, *ae, *cc;
     ngx_http_core_loc_conf_t  *clcf;
 
     r->gzip_tested = 1;
@@ -2118,30 +2117,30 @@ ngx_http_gzip_ok(ngx_http_request_t *r)
         return NGX_DECLINED;
     }
 
-    cc = &r->headers_out.cache_control;
+    cc = r->headers_out.cache_control;
 
-    if (cc->elts) {
+    if (cc) {
 
         if ((p & NGX_HTTP_GZIP_PROXIED_NO_CACHE)
-            && ngx_http_parse_multi_header_lines(cc, &ngx_http_gzip_no_cache,
+            && ngx_http_parse_multi_header_lines(r, cc, &ngx_http_gzip_no_cache,
                                                  NULL)
-               >= 0)
+               != NULL)
         {
             goto ok;
         }
 
         if ((p & NGX_HTTP_GZIP_PROXIED_NO_STORE)
-            && ngx_http_parse_multi_header_lines(cc, &ngx_http_gzip_no_store,
+            && ngx_http_parse_multi_header_lines(r, cc, &ngx_http_gzip_no_store,
                                                  NULL)
-               >= 0)
+               != NULL)
         {
             goto ok;
         }
 
         if ((p & NGX_HTTP_GZIP_PROXIED_PRIVATE)
-            && ngx_http_parse_multi_header_lines(cc, &ngx_http_gzip_private,
+            && ngx_http_parse_multi_header_lines(r, cc, &ngx_http_gzip_private,
                                                  NULL)
-               >= 0)
+               != NULL)
         {
             goto ok;
         }
@@ -2712,12 +2711,12 @@ ngx_http_set_disable_symlinks(ngx_http_request_t *r,
 
 ngx_int_t
 ngx_http_get_forwarded_addr(ngx_http_request_t *r, ngx_addr_t *addr,
-    ngx_array_t *headers, ngx_str_t *value, ngx_array_t *proxies,
+    ngx_table_elt_t *headers, ngx_str_t *value, ngx_array_t *proxies,
     int recursive)
 {
-    ngx_int_t          rc;
-    ngx_uint_t         i, found;
-    ngx_table_elt_t  **h;
+    ngx_int_t         rc;
+    ngx_uint_t        found;
+    ngx_table_elt_t  *h, *next;
 
     if (headers == NULL) {
         return ngx_http_get_forwarded_addr_internal(r, addr, value->data,
@@ -2725,16 +2724,23 @@ ngx_http_get_forwarded_addr(ngx_http_request_t *r, ngx_addr_t *addr,
                                                     recursive);
     }
 
-    i = headers->nelts;
-    h = headers->elts;
+    /* revert headers order */
+
+    for (h = headers, headers = NULL; h; h = next) {
+        next = h->next;
+        h->next = headers;
+        headers = h;
+    }
+
+    /* iterate over all headers in reverse order */
 
     rc = NGX_DECLINED;
 
     found = 0;
 
-    while (i-- > 0) {
-        rc = ngx_http_get_forwarded_addr_internal(r, addr, h[i]->value.data,
-                                                  h[i]->value.len, proxies,
+    for (h = headers; h; h = h->next) {
+        rc = ngx_http_get_forwarded_addr_internal(r, addr, h->value.data,
+                                                  h->value.len, proxies,
                                                   recursive);
 
         if (!recursive) {
@@ -2753,6 +2759,14 @@ ngx_http_get_forwarded_addr(ngx_http_request_t *r, ngx_addr_t *addr,
         found = 1;
     }
 
+    /* restore headers order */
+
+    for (h = headers, headers = NULL; h; h = next) {
+        next = h->next;
+        h->next = headers;
+        headers = h;
+    }
+
     return rc;
 }
 
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 7ba64947b..49bbd4aa9 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -529,7 +529,7 @@ ngx_int_t ngx_http_set_disable_symlinks(ngx_http_request_t *r,
     ngx_http_core_loc_conf_t *clcf, ngx_str_t *path, ngx_open_file_info_t *of);
 
 ngx_int_t ngx_http_get_forwarded_addr(ngx_http_request_t *r, ngx_addr_t *addr,
-    ngx_array_t *headers, ngx_str_t *value, ngx_array_t *proxies,
+    ngx_table_elt_t *headers, ngx_str_t *value, ngx_array_t *proxies,
     int recursive);
 
 ngx_int_t ngx_http_link_multi_headers(ngx_http_request_t *r);
diff --git a/src/http/ngx_http_parse.c b/src/http/ngx_http_parse.c
index 6460da293..d4f2dae87 100644
--- a/src/http/ngx_http_parse.c
+++ b/src/http/ngx_http_parse.c
@@ -1960,27 +1960,24 @@ unsafe:
 }
 
 
-ngx_int_t
-ngx_http_parse_multi_header_lines(ngx_array_t *headers, ngx_str_t *name,
-    ngx_str_t *value)
+ngx_table_elt_t *
+ngx_http_parse_multi_header_lines(ngx_http_request_t *r,
+    ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value)
 {
-    ngx_uint_t         i;
-    u_char            *start, *last, *end, ch;
-    ngx_table_elt_t  **h;
-
-    h = headers->elts;
+    u_char           *start, *last, *end, ch;
+    ngx_table_elt_t  *h;
 
-    for (i = 0; i < headers->nelts; i++) {
+    for (h = headers; h; h = h->next) {
 
-        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, headers->pool->log, 0,
-                       "parse header: \"%V: %V\"", &h[i]->key, &h[i]->value);
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "parse header: \"%V: %V\"", &h->key, &h->value);
 
-        if (name->len > h[i]->value.len) {
+        if (name->len > h->value.len) {
             continue;
         }
 
-        start = h[i]->value.data;
-        end = h[i]->value.data + h[i]->value.len;
+        start = h->value.data;
+        end = h->value.data + h->value.len;
 
         while (start < end) {
 
@@ -1994,7 +1991,7 @@ ngx_http_parse_multi_header_lines(ngx_array_t *headers, ngx_str_t *name,
 
             if (value == NULL) {
                 if (start == end || *start == ',') {
-                    return i;
+                    return h;
                 }
 
                 goto skip;
@@ -2014,7 +2011,7 @@ ngx_http_parse_multi_header_lines(ngx_array_t *headers, ngx_str_t *name,
             value->len = last - start;
             value->data = start;
 
-            return i;
+            return h;
 
         skip:
 
@@ -2029,31 +2026,28 @@ ngx_http_parse_multi_header_lines(ngx_array_t *headers, ngx_str_t *name,
         }
     }
 
-    return NGX_DECLINED;
+    return NULL;
 }
 
 
-ngx_int_t
-ngx_http_parse_set_cookie_lines(ngx_array_t *headers, ngx_str_t *name,
-    ngx_str_t *value)
+ngx_table_elt_t *
+ngx_http_parse_set_cookie_lines(ngx_http_request_t *r,
+    ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value)
 {
-    ngx_uint_t         i;
-    u_char            *start, *last, *end;
-    ngx_table_elt_t  **h;
-
-    h = headers->elts;
+    u_char           *start, *last, *end;
+    ngx_table_elt_t  *h;
 
-    for (i = 0; i < headers->nelts; i++) {
+    for (h = headers; h; h = h->next) {
 
-        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, headers->pool->log, 0,
-                       "parse header: \"%V: %V\"", &h[i]->key, &h[i]->value);
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "parse header: \"%V: %V\"", &h->key, &h->value);
 
-        if (name->len >= h[i]->value.len) {
+        if (name->len >= h->value.len) {
             continue;
         }
 
-        start = h[i]->value.data;
-        end = h[i]->value.data + h[i]->value.len;
+        start = h->value.data;
+        end = h->value.data + h->value.len;
 
         if (ngx_strncasecmp(start, name->data, name->len) != 0) {
             continue;
@@ -2077,10 +2071,10 @@ ngx_http_parse_set_cookie_lines(ngx_array_t *headers, ngx_str_t *name,
         value->len = last - start;
         value->data = start;
 
-        return i;
+        return h;
     }
 
-    return NGX_DECLINED;
+    return NULL;
 }
 
 
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index 44e4d89de..57fdd2f66 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -196,7 +196,7 @@ ngx_http_header_t  ngx_http_headers_in[] = {
                  ngx_http_process_header_line },
 #endif
 
-    { ngx_string("Cookie"), offsetof(ngx_http_headers_in_t, cookies),
+    { ngx_string("Cookie"), offsetof(ngx_http_headers_in_t, cookie),
                  ngx_http_process_multi_header_lines },
 
     { ngx_null_string, 0, NULL }
@@ -1744,6 +1744,7 @@ ngx_http_process_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
 
     if (*ph == NULL) {
         *ph = h;
+        h->next = NULL;
     }
 
     return NGX_OK;
@@ -1760,6 +1761,7 @@ ngx_http_process_unique_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
 
     if (*ph == NULL) {
         *ph = h;
+        h->next = NULL;
         return NGX_OK;
     }
 
@@ -1792,6 +1794,7 @@ ngx_http_process_host(ngx_http_request_t *r, ngx_table_elt_t *h,
     }
 
     r->headers_in.host = h;
+    h->next = NULL;
 
     host = h->value;
 
@@ -1853,6 +1856,7 @@ ngx_http_process_user_agent(ngx_http_request_t *r, ngx_table_elt_t *h,
     }
 
     r->headers_in.user_agent = h;
+    h->next = NULL;
 
     /* check some widespread browsers while the header is in CPU cache */
 
@@ -1919,27 +1923,15 @@ static ngx_int_t
 ngx_http_process_multi_header_lines(ngx_http_request_t *r, ngx_table_elt_t *h,
     ngx_uint_t offset)
 {
-    ngx_array_t       *headers;
     ngx_table_elt_t  **ph;
 
-    headers = (ngx_array_t *) ((char *) &r->headers_in + offset);
-
-    if (headers->elts == NULL) {
-        if (ngx_array_init(headers, r->pool, 1, sizeof(ngx_table_elt_t *))
-            != NGX_OK)
-        {
-            ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
-            return NGX_ERROR;
-        }
-    }
+    ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
 
-    ph = ngx_array_push(headers);
-    if (ph == NULL) {
-        ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
-        return NGX_ERROR;
-    }
+    while (*ph) { ph = &(*ph)->next; }
 
     *ph = h;
+    h->next = NULL;
+
     return NGX_OK;
 }
 
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 52165793a..8c9eed249 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -212,7 +212,7 @@ typedef struct {
     ngx_table_elt_t                  *keep_alive;
 
 #if (NGX_HTTP_X_FORWARDED_FOR)
-    ngx_array_t                       x_forwarded_for;
+    ngx_table_elt_t                  *x_forwarded_for;
 #endif
 
 #if (NGX_HTTP_REALIP)
@@ -231,11 +231,11 @@ typedef struct {
     ngx_table_elt_t                  *date;
 #endif
 
+    ngx_table_elt_t                  *cookie;
+
     ngx_str_t                         user;
     ngx_str_t                         passwd;
 
-    ngx_array_t                       cookies;
-
     ngx_str_t                         server;
     off_t                             content_length_n;
     time_t                            keep_alive_n;
@@ -274,6 +274,9 @@ typedef struct {
     ngx_table_elt_t                  *expires;
     ngx_table_elt_t                  *etag;
 
+    ngx_table_elt_t                  *cache_control;
+    ngx_table_elt_t                  *link;
+
     ngx_str_t                        *override_charset;
 
     size_t                            content_type_len;
@@ -282,9 +285,6 @@ typedef struct {
     u_char                           *content_type_lowcase;
     ngx_uint_t                        content_type_hash;
 
-    ngx_array_t                       cache_control;
-    ngx_array_t                       link;
-
     off_t                             content_length_n;
     off_t                             content_offset;
     time_t                            date_time;
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 46fde8396..99d72be07 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -246,7 +246,7 @@ static ngx_http_upstream_header_t  ngx_http_upstream_headers_in[] = {
 
     { ngx_string("Set-Cookie"),
                  ngx_http_upstream_process_set_cookie,
-                 offsetof(ngx_http_upstream_headers_in_t, cookies),
+                 offsetof(ngx_http_upstream_headers_in_t, set_cookie),
                  ngx_http_upstream_rewrite_set_cookie, 0, 1 },
 
     { ngx_string("Content-Disposition"),
@@ -4666,26 +4666,16 @@ static ngx_int_t
 ngx_http_upstream_process_set_cookie(ngx_http_request_t *r, ngx_table_elt_t *h,
     ngx_uint_t offset)
 {
-    ngx_array_t           *pa;
     ngx_table_elt_t      **ph;
     ngx_http_upstream_t   *u;
 
     u = r->upstream;
-    pa = &u->headers_in.cookies;
+    ph = &u->headers_in.set_cookie;
 
-    if (pa->elts == NULL) {
-        if (ngx_array_init(pa, r->pool, 1, sizeof(ngx_table_elt_t *)) != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
-    }
-
-    ph = ngx_array_push(pa);
-    if (ph == NULL) {
-        return NGX_ERROR;
-    }
+    while (*ph) { ph = &(*ph)->next; }
 
     *ph = h;
+    h->next = NULL;
 
 #if (NGX_HTTP_CACHE)
     if (!(u->conf->ignore_headers & NGX_HTTP_UPSTREAM_IGN_SET_COOKIE)) {
@@ -4701,26 +4691,16 @@ static ngx_int_t
 ngx_http_upstream_process_cache_control(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset)
 {
-    ngx_array_t          *pa;
     ngx_table_elt_t     **ph;
     ngx_http_upstream_t  *u;
 
     u = r->upstream;
-    pa = &u->headers_in.cache_control;
+    ph = &u->headers_in.cache_control;
 
-    if (pa->elts == NULL) {
-        if (ngx_array_init(pa, r->pool, 2, sizeof(ngx_table_elt_t *)) != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
-    }
-
-    ph = ngx_array_push(pa);
-    if (ph == NULL) {
-        return NGX_ERROR;
-    }
+    while (*ph) { ph = &(*ph)->next; }
 
     *ph = h;
+    h->next = NULL;
 
 #if (NGX_HTTP_CACHE)
     {
@@ -5103,18 +5083,8 @@ static ngx_int_t
 ngx_http_upstream_copy_multi_header_lines(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset)
 {
-    ngx_array_t      *pa;
     ngx_table_elt_t  *ho, **ph;
 
-    pa = (ngx_array_t *) ((char *) &r->headers_out + offset);
-
-    if (pa->elts == NULL) {
-        if (ngx_array_init(pa, r->pool, 2, sizeof(ngx_table_elt_t *)) != NGX_OK)
-        {
-            return NGX_ERROR;
-        }
-    }
-
     ho = ngx_list_push(&r->headers_out.headers);
     if (ho == NULL) {
         return NGX_ERROR;
@@ -5122,12 +5092,12 @@ ngx_http_upstream_copy_multi_header_lines(ngx_http_request_t *r,
 
     *ho = *h;
 
-    ph = ngx_array_push(pa);
-    if (ph == NULL) {
-        return NGX_ERROR;
-    }
+    ph = (ngx_table_elt_t **) ((char *) &r->headers_out + offset);
+
+    while (*ph) { ph = &(*ph)->next; }
 
     *ph = ho;
+    ho->next = NULL;
 
     return NGX_OK;
 }
@@ -5740,9 +5710,9 @@ ngx_http_upstream_cookie_variable(ngx_http_request_t *r,
     s.len = name->len - (sizeof("upstream_cookie_") - 1);
     s.data = name->data + sizeof("upstream_cookie_") - 1;
 
-    if (ngx_http_parse_set_cookie_lines(&r->upstream->headers_in.cookies,
+    if (ngx_http_parse_set_cookie_lines(r, r->upstream->headers_in.set_cookie,
                                         &s, &cookie)
-        == NGX_DECLINED)
+        == NULL)
     {
         v->not_found = 1;
         return NGX_OK;
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index 3db7b0643..18a9c570b 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -289,8 +289,8 @@ typedef struct {
     ngx_table_elt_t                 *content_encoding;
 #endif
 
-    ngx_array_t                      cache_control;
-    ngx_array_t                      cookies;
+    ngx_table_elt_t                 *cache_control;
+    ngx_table_elt_t                 *set_cookie;
 
     off_t                            content_length_n;
     time_t                           last_modified_time;
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index b0f06ac7c..69462f10c 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -183,7 +183,7 @@ static ngx_http_variable_t  ngx_http_core_variables[] = {
 #endif
 
     { ngx_string("http_cookie"), NULL, ngx_http_variable_cookies,
-      offsetof(ngx_http_request_t, headers_in.cookies), 0, 0 },
+      offsetof(ngx_http_request_t, headers_in.cookie), 0, 0 },
 
     { ngx_string("content_length"), NULL, ngx_http_variable_content_length,
       0, 0, 0 },
@@ -846,26 +846,21 @@ static ngx_int_t
 ngx_http_variable_headers_internal(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data, u_char sep)
 {
-    size_t             len;
-    u_char            *p, *end;
-    ngx_uint_t         i, n;
-    ngx_array_t       *a;
-    ngx_table_elt_t  **h;
-
-    a = (ngx_array_t *) ((char *) r + data);
+    size_t            len;
+    u_char           *p;
+    ngx_table_elt_t  *h, *th;
 
-    n = a->nelts;
-    h = a->elts;
+    h = *(ngx_table_elt_t **) ((char *) r + data);
 
     len = 0;
 
-    for (i = 0; i < n; i++) {
+    for (th = h; th; th = th->next) {
 
-        if (h[i]->hash == 0) {
+        if (th->hash == 0) {
             continue;
         }
 
-        len += h[i]->value.len + 2;
+        len += th->value.len + 2;
     }
 
     if (len == 0) {
@@ -879,9 +874,9 @@ ngx_http_variable_headers_internal(ngx_http_request_t *r,
     v->no_cacheable = 0;
     v->not_found = 0;
 
-    if (n == 1) {
-        v->len = (*h)->value.len;
-        v->data = (*h)->value.data;
+    if (h->next == NULL) {
+        v->len = h->value.len;
+        v->data = h->value.data;
 
         return NGX_OK;
     }
@@ -894,17 +889,15 @@ ngx_http_variable_headers_internal(ngx_http_request_t *r,
     v->len = len;
     v->data = p;
 
-    end = p + len;
-
-    for (i = 0; /* void */ ; i++) {
+    for (th = h; th; th = th->next) {
 
-        if (h[i]->hash == 0) {
+        if (th->hash == 0) {
             continue;
         }
 
-        p = ngx_copy(p, h[i]->value.data, h[i]->value.len);
+        p = ngx_copy(p, th->value.data, th->value.len);
 
-        if (p == end) {
+        if (th->next == NULL) {
             break;
         }
 
@@ -1102,8 +1095,8 @@ ngx_http_variable_cookie(ngx_http_request_t *r, ngx_http_variable_value_t *v,
     s.len = name->len - (sizeof("cookie_") - 1);
     s.data = name->data + sizeof("cookie_") - 1;
 
-    if (ngx_http_parse_multi_header_lines(&r->headers_in.cookies, &s, &cookie)
-        == NGX_DECLINED)
+    if (ngx_http_parse_multi_header_lines(r, r->headers_in.cookie, &s, &cookie)
+        == NULL)
     {
         v->not_found = 1;
         return NGX_OK;
diff --git a/src/http/v2/ngx_http_v2_filter_module.c b/src/http/v2/ngx_http_v2_filter_module.c
index 62b6a047c..5f8626a40 100644
--- a/src/http/v2/ngx_http_v2_filter_module.c
+++ b/src/http/v2/ngx_http_v2_filter_module.c
@@ -674,14 +674,14 @@ ngx_http_v2_header_filter(ngx_http_request_t *r)
 static ngx_int_t
 ngx_http_v2_push_resources(ngx_http_request_t *r)
 {
-    u_char                     *start, *end, *last;
-    ngx_int_t                   rc;
-    ngx_str_t                   path;
-    ngx_uint_t                  i, push;
-    ngx_table_elt_t           **h;
-    ngx_http_v2_loc_conf_t     *h2lcf;
-    ngx_http_complex_value_t   *pushes;
-    ngx_str_t                   binary[NGX_HTTP_V2_PUSH_HEADERS];
+    u_char                    *start, *end, *last;
+    ngx_int_t                  rc;
+    ngx_str_t                  path;
+    ngx_uint_t                 i, push;
+    ngx_table_elt_t           *h;
+    ngx_http_v2_loc_conf_t    *h2lcf;
+    ngx_http_complex_value_t  *pushes;
+    ngx_str_t                  binary[NGX_HTTP_V2_PUSH_HEADERS];
 
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                    "http2 push resources");
@@ -725,15 +725,13 @@ ngx_http_v2_push_resources(ngx_http_request_t *r)
         return NGX_OK;
     }
 
-    h = r->headers_out.link.elts;
-
-    for (i = 0; i < r->headers_out.link.nelts; i++) {
+    for (h = r->headers_out.link; h; h = h->next) {
 
         ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                       "http2 parse link: \"%V\"", &h[i]->value);
+                       "http2 parse link: \"%V\"", &h->value);
 
-        start = h[i]->value.data;
-        end = h[i]->value.data + h[i]->value.len;
+        start = h->value.data;
+        end = h->value.data + h->value.len;
 
     next_link: