efi_loader: net: add support to send http requests and parse http headers

Add network-stack agnostic way to send an http request and
parse http headers from efi drivers. This uses wget as a
backend and communicates with it via efi_wget_info.

The function efi_net_do_request allocates a buffer on behalf of an
efi application using efi_alloc and passes it to wget to receive
the data. If the method is GET and the buffer is too small, it
re-allocates the buffer based on the last received Content-Length
header and tries again. If the method is HEAD it just issues one
request. So issuing a HEAD request (to update Content-Length) and
then a GET request is preferred but not required.

The function efi_net_parse_headers parses a raw buffer containing
an http header into an array of EFI specific 'http_header' structs.

Signed-off-by: Adriano Cordova <adrianox@gmail.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 0da0248..b6f865c 100644 (file)
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -16,6 +16,7 @@
 #include <image.h>
 #include <pe.h>
 #include <linux/list.h>
+#include <linux/sizes.h>
 #include <linux/oid_registry.h>
 
 struct blk_desc;
@@ -136,6 +137,18 @@ void efi_net_get_addr(struct efi_ipv4_address *ip,
 void efi_net_set_addr(struct efi_ipv4_address *ip,
                      struct efi_ipv4_address *mask,
                      struct efi_ipv4_address *gw);
+efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method, void **buffer,
+                               u32 *status_code, ulong *file_size, char *headers_buffer);
+#define MAX_HTTP_HEADERS_SIZE SZ_64K
+#define MAX_HTTP_HEADERS 100
+#define MAX_HTTP_HEADER_NAME 128
+#define MAX_HTTP_HEADER_VALUE 512
+struct http_header {
+       uchar name[MAX_HTTP_HEADER_NAME];
+       uchar value[MAX_HTTP_HEADER_VALUE];
+};
+
+void efi_net_parse_headers(ulong *num_headers, struct http_header *headers);
 #else
 static inline void efi_net_get_dp(struct efi_device_path **dp) { }
 static inline void efi_net_get_addr(struct efi_ipv4_address *ip,

diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
index e8af2e3..368f62c 100644 (file)
--- a/lib/efi_loader/efi_net.c
+++ b/lib/efi_loader/efi_net.c
@@ -17,6 +17,7 @@
 
 #include <efi_loader.h>
 #include <dm.h>
+#include <linux/sizes.h>
 #include <malloc.h>
 #include <vsprintf.h>
 #include <net.h>
@@ -40,6 +41,12 @@ static struct efi_net_obj *netobj;
  */
 static struct efi_device_path *net_dp;
 
+static struct wget_http_info efi_wget_info = {
+       .set_bootdev = false,
+       .check_buffer_size = true,
+
+};
+
 /*
  * The notification function of this event is called in every timer cycle
  * to check if a new network packet has been received.
@@ -1175,3 +1182,151 @@ void efi_net_set_addr(struct efi_ipv4_address *ip,
                memcpy(&net_netmask, mask, sizeof(*mask));
 #endif
 }
+
+/**
+ * efi_net_set_buffer() - allocate a buffer of min 64K
+ *
+ * @buffer:    allocated buffer
+ * @size:      desired buffer size
+ * Return:     status code
+ */
+static efi_status_t efi_net_set_buffer(void **buffer, size_t size)
+{
+       efi_status_t ret = EFI_SUCCESS;
+
+       if (size < SZ_64K)
+               size = SZ_64K;
+
+       efi_free_pool(*buffer);
+
+       *buffer = efi_alloc(size);
+       if (!*buffer)
+               ret = EFI_OUT_OF_RESOURCES;
+
+       efi_wget_info.buffer_size = (ulong)size;
+
+       return ret;
+}
+
+/**
+ * efi_net_parse_headers() - parse HTTP headers
+ *
+ * Parses the raw buffer efi_wget_info.headers into an array headers
+ * of efi structs http_headers. The array should be at least
+ * MAX_HTTP_HEADERS long.
+ *
+ * @num_headers:       number of headers
+ * @headers:           caller provided array of struct http_headers
+ */
+void efi_net_parse_headers(ulong *num_headers, struct http_header *headers)
+{
+       if (!num_headers || !headers)
+               return;
+
+       // Populate info with http headers.
+       *num_headers = 0;
+       const uchar *line_start = efi_wget_info.headers;
+       const uchar *line_end;
+       ulong count;
+       struct http_header *current_header;
+       const uchar *separator;
+       size_t name_length, value_length;
+
+       // Skip the first line (request or status line)
+       line_end = strstr(line_start, "\r\n");
+
+       if (line_end)
+               line_start = line_end + 2;
+
+       while ((line_end = strstr(line_start, "\r\n")) != NULL) {
+               count = *num_headers;
+               if (line_start == line_end || count >= MAX_HTTP_HEADERS)
+                       break;
+               current_header = headers + count;
+               separator = strchr(line_start, ':');
+               if (separator) {
+                       name_length = separator - line_start;
+                       ++separator;
+                       while (*separator == ' ')
+                               ++separator;
+                       value_length = line_end - separator;
+                       if (name_length < MAX_HTTP_HEADER_NAME &&
+                           value_length < MAX_HTTP_HEADER_VALUE) {
+                               strncpy(current_header->name, line_start, name_length);
+                               current_header->name[name_length] = '\0';
+                               strncpy(current_header->value, separator, value_length);
+                               current_header->value[value_length] = '\0';
+                               (*num_headers)++;
+                       }
+               }
+               line_start = line_end + 2;
+       }
+}
+
+/**
+ * efi_net_do_request() - issue an HTTP request using wget
+ *
+ * @url:               url
+ * @method:            HTTP method
+ * @buffer:            data buffer
+ * @status_code:       HTTP status code
+ * @file_size:         file size in bytes
+ * @headers_buffer:    headers buffer
+ * Return:             status code
+ */
+efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method, void **buffer,
+                               u32 *status_code, ulong *file_size, char *headers_buffer)
+{
+       efi_status_t ret = EFI_SUCCESS;
+       int wget_ret;
+       static bool last_head;
+
+       if (!buffer || !file_size)
+               return EFI_ABORTED;
+
+       efi_wget_info.method = (enum wget_http_method)method;
+       efi_wget_info.headers = headers_buffer;
+
+       switch (method) {
+       case HTTP_METHOD_GET:
+               ret = efi_net_set_buffer(buffer, last_head ? (size_t)efi_wget_info.hdr_cont_len : 0);
+               if (ret != EFI_SUCCESS)
+                       goto out;
+               wget_ret = wget_request((ulong)*buffer, url, &efi_wget_info);
+               if ((ulong)efi_wget_info.hdr_cont_len > efi_wget_info.buffer_size) {
+                       // Try again with updated buffer size
+                       ret = efi_net_set_buffer(buffer, (size_t)efi_wget_info.hdr_cont_len);
+                       if (ret != EFI_SUCCESS)
+                               goto out;
+                       if (wget_request((ulong)*buffer, url, &efi_wget_info)) {
+                               efi_free_pool(*buffer);
+                               ret = EFI_DEVICE_ERROR;
+                               goto out;
+                       }
+               } else if (wget_ret) {
+                       efi_free_pool(*buffer);
+                       ret = EFI_DEVICE_ERROR;
+                       goto out;
+               }
+               // Pass the actual number of received bytes to the application
+               *file_size = efi_wget_info.file_size;
+               *status_code = efi_wget_info.status_code;
+               last_head = false;
+               break;
+       case HTTP_METHOD_HEAD:
+               ret = efi_net_set_buffer(buffer, 0);
+               if (ret != EFI_SUCCESS)
+                       goto out;
+               wget_request((ulong)*buffer, url, &efi_wget_info);
+               *file_size = 0;
+               *status_code = efi_wget_info.status_code;
+               last_head = true;
+               break;
+       default:
+               ret = EFI_UNSUPPORTED;
+               break;
+       }
+
+out:
+       return ret;
+}