[PATCH v2 10/15] efi_loader: net: add support to send http requests and parse http headers

Adriano Cordova
2024-11-08T15:57:46Z

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 the struct wget_http_info
'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>
---
include/efi_loader.h | 13 ++++
lib/efi_loader/efi_net.c | 128 +++++++++++++++++++++++++++++++++++++++
2 files changed, 141 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index c37c1a4660..a19505d4cc 100644
--- 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,
+ ulong *buffer, 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_set_dp(const char *dev, const char *server) { }
static inline void efi_net_get_dp(void **dp) { }
diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
index d4570d4d7c..43b57b63d5 100644
--- 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>
@@ -1117,3 +1118,130 @@ void efi_net_set_addr(struct efi_ipv4_address *ip,
memcpy((void *)&net_netmask, (void *)mask, 4);
#endif
}
+
+static efi_status_t efi_net_set_buffer(ulong *buffer, ulong size)
+{
+ efi_status_t ret = EFI_SUCCESS;
+
+ if (size < SZ_64K)
+ size = SZ_64K;
+
+ efi_free_pool((void *)*buffer);
+
+ *buffer = (ulong)efi_alloc(size);
+ if (!*buffer)
+ ret = EFI_OUT_OF_RESOURCES;
+
+ wget_info.buffer_size = size;
+ //debug("efi_net: set buffer of size %lu at %lu\n", size, *buffer);
+ return ret;
+}
+
+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 = 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_status_t efi_net_do_request(u8 *url, enum efi_http_method method,
+ ulong *buffer, ulong *file_size,
+ char *headers_buffer)
+{
+ efi_status_t ret = EFI_SUCCESS;
+ int wget_ret;
+ static bool last_head;
+ bool old_setbootdev, old_bufsize;
+
+ if (!buffer || !file_size)
+ return EFI_ABORTED;
+
+ wget_info.method = (enum wget_http_method)method;
+ wget_info.headers = headers_buffer;
+ // Do not set u-boot bootdevice when using wget from efi
+ old_setbootdev = wget_info.set_bootdev;
+ old_bufsize = wget_info.check_buffer_size;
+ wget_info.set_bootdev = false;
+ wget_info.check_buffer_size = true;
+
+ switch (method) {
+ case HTTP_METHOD_GET:
+ ret = efi_net_set_buffer(buffer, last_head ? wget_info.hdr_cont_len : 0);
+ if (ret != EFI_SUCCESS)
+ goto out;
+ wget_ret = wget_with_dns((ulong)*buffer, url);
+ if ((ulong)wget_info.hdr_cont_len > wget_info.buffer_size) {
+ // Try again with updated buffer size
+ ret = efi_net_set_buffer(buffer, (ulong)wget_info.hdr_cont_len);
+ if (ret != EFI_SUCCESS)
+ goto out;
+ if (wget_with_dns((ulong)*buffer, url)) {
+ efi_free_pool((void *)*buffer);
+ ret = EFI_DEVICE_ERROR;
+ goto out;
+ }
+ } else if (wget_ret) {
+ efi_free_pool((void *)*buffer);
+ ret = EFI_DEVICE_ERROR;
+ goto out;
+ }
+ // Pass the actual number of received bytes to the application
+ *file_size = wget_info.file_size;
+ last_head = false;
+ break;
+ case HTTP_METHOD_HEAD:
+ ret = efi_net_set_buffer(buffer, 0);
+ if (ret != EFI_SUCCESS)
+ goto out;
+ wget_with_dns((ulong)*buffer, url);
+ *file_size = 0;
+ last_head = true;
+ break;
+ default:
+ ret = EFI_UNSUPPORTED;
+ break;
+ }
+
+out:
+ wget_info.set_bootdev = old_setbootdev;
+ wget_info.check_buffer_size = old_bufsize;
+ return ret;
+}
--
2.43.0