[PATCH 07 of 20] All non-unique input headers are now linked lists

Sergey Kandaurov pluknet at nginx.com
Wed May 11 19:40:48 UTC 2022


On Thu, Apr 21, 2022 at 01:18:47AM +0300, Maxim Dounin wrote:
> # HG changeset patch
> # User Maxim Dounin <mdounin at mdounin.ru>
> # Date 1650492324 -10800
> #      Thu Apr 21 01:05:24 2022 +0300
> # Node ID 238d1f5f438735432822689605fa37b1b0e01517
> # Parent  50fe52f516ff9c148aa9e7dfcc1c31cc6a4929ae
> All non-unique input headers are now linked lists.
> 
> The ngx_http_process_multi_header_lines() function is removed, as it is
> exactly equivalent to ngx_http_process_header_line().  Similarly,
> ngx_http_variable_header() is used instead of ngx_http_variable_headers().
> 
> diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
> --- a/src/http/ngx_http_request.c
> +++ b/src/http/ngx_http_request.c
> @@ -22,8 +22,6 @@ static ngx_int_t ngx_http_process_header
>      ngx_table_elt_t *h, ngx_uint_t offset);
>  static ngx_int_t ngx_http_process_unique_header_line(ngx_http_request_t *r,
>      ngx_table_elt_t *h, ngx_uint_t offset);
> -static ngx_int_t ngx_http_process_multi_header_lines(ngx_http_request_t *r,
> -    ngx_table_elt_t *h, ngx_uint_t offset);
>  static ngx_int_t ngx_http_process_host(ngx_http_request_t *r,
>      ngx_table_elt_t *h, ngx_uint_t offset);
>  static ngx_int_t ngx_http_process_connection(ngx_http_request_t *r,
> @@ -164,7 +162,7 @@ ngx_http_header_t  ngx_http_headers_in[]
>  #if (NGX_HTTP_X_FORWARDED_FOR)
>      { ngx_string("X-Forwarded-For"),
>                   offsetof(ngx_http_headers_in_t, x_forwarded_for),
> -                 ngx_http_process_multi_header_lines },
> +                 ngx_http_process_header_line },
>  #endif
>  
>  #if (NGX_HTTP_REALIP)
> @@ -197,7 +195,7 @@ ngx_http_header_t  ngx_http_headers_in[]
>  #endif
>  
>      { ngx_string("Cookie"), offsetof(ngx_http_headers_in_t, cookie),
> -                 ngx_http_process_multi_header_lines },
> +                 ngx_http_process_header_line },
>  
>      { ngx_null_string, 0, NULL }
>  };
> @@ -1742,10 +1740,10 @@ ngx_http_process_header_line(ngx_http_re
>  
>      ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
>  
> -    if (*ph == NULL) {
> -        *ph = h;
> -        h->next = NULL;
> -    }
> +    while (*ph) { ph = &(*ph)->next; }
> +
> +    *ph = h;
> +    h->next = NULL;
>  
>      return NGX_OK;
>  }

Essentially, this makes the following headers multi-valuable,
which are specified (or otherwise implied) to have a single value:
Referer, Content-Type, Range, Keep-Alive, X-Real-IP,
also DAV headers (including Date) and User-Agent (as below).
This makes proxying comma-delimited header values to backend, such as:
  Date: Wed, 11 May 2022 19:29:54 GMT
  Date: Wed, 11 May 2022 19:29:55 GMT
->
  HTTP_DATE: Wed, 11 May 2022 19:29:54 GMT, Wed, 11 May 2022 19:29:55 GMT

Convert them to ngx_http_process_unique_header_line() ?

> @@ -1851,13 +1849,10 @@ ngx_http_process_user_agent(ngx_http_req
>  {
>      u_char  *user_agent, *msie;
>  
> -    if (r->headers_in.user_agent) {
> -        return NGX_OK;
> +    if (ngx_http_process_header_line(r, h, offset) != NGX_OK) {
> +        return NGX_ERROR;
>      }
>  
> -    r->headers_in.user_agent = h;
> -    h->next = NULL;
> -
>      /* check some widespread browsers while the header is in CPU cache */
>  
>      user_agent = h->value.data;
> @@ -1919,23 +1914,6 @@ ngx_http_process_user_agent(ngx_http_req
>  }
>  
>  
> -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_table_elt_t  **ph;
> -
> -    ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
> -
> -    while (*ph) { ph = &(*ph)->next; }
> -
> -    *ph = h;
> -    h->next = NULL;
> -
> -    return NGX_OK;
> -}
> -
> -
>  ngx_int_t
>  ngx_http_process_request_header(ngx_http_request_t *r)
>  {
> diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
> --- a/src/http/ngx_http_variables.c
> +++ b/src/http/ngx_http_variables.c
> @@ -27,8 +27,6 @@ static ngx_int_t ngx_http_variable_heade
>  
>  static ngx_int_t ngx_http_variable_cookies(ngx_http_request_t *r,
>      ngx_http_variable_value_t *v, uintptr_t data);
> -static ngx_int_t ngx_http_variable_headers(ngx_http_request_t *r,
> -    ngx_http_variable_value_t *v, uintptr_t data);
>  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);
>  
> @@ -178,7 +176,7 @@ static ngx_http_variable_t  ngx_http_cor
>  #endif
>  
>  #if (NGX_HTTP_X_FORWARDED_FOR)
> -    { ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_headers,
> +    { ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_header,
>        offsetof(ngx_http_request_t, headers_in.x_forwarded_for), 0, 0 },
>  #endif
>  
> @@ -327,10 +325,10 @@ static ngx_http_variable_t  ngx_http_cor
>      { ngx_string("sent_http_transfer_encoding"), NULL,
>        ngx_http_variable_sent_transfer_encoding, 0, 0, 0 },
>  
> -    { ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_headers,
> +    { ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_header,
>        offsetof(ngx_http_request_t, headers_out.cache_control), 0, 0 },
>  
> -    { ngx_string("sent_http_link"), NULL, ngx_http_variable_headers,
> +    { ngx_string("sent_http_link"), NULL, ngx_http_variable_header,
>        offsetof(ngx_http_request_t, headers_out.link), 0, 0 },
>  
>      { ngx_string("limit_rate"), ngx_http_variable_set_limit_rate,
> @@ -807,22 +805,7 @@ static ngx_int_t
>  ngx_http_variable_header(ngx_http_request_t *r, ngx_http_variable_value_t *v,
>      uintptr_t data)
>  {
> -    ngx_table_elt_t  *h;
> -
> -    h = *(ngx_table_elt_t **) ((char *) r + data);
> -
> -    if (h) {
> -        v->len = h->value.len;
> -        v->valid = 1;
> -        v->no_cacheable = 0;
> -        v->not_found = 0;
> -        v->data = h->value.data;
> -
> -    } else {
> -        v->not_found = 1;
> -    }
> -
> -    return NGX_OK;
> +    return ngx_http_variable_headers_internal(r, v, data, ',');
>  }
>  
>  
> @@ -835,14 +818,6 @@ ngx_http_variable_cookies(ngx_http_reque
>  
>  
>  static ngx_int_t
> -ngx_http_variable_headers(ngx_http_request_t *r,
> -    ngx_http_variable_value_t *v, uintptr_t data)
> -{
> -    return ngx_http_variable_headers_internal(r, v, data, ',');
> -}
> -
> -
> -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)
>  {
> 



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