[PATCH v3 10/15] efi_loader: net: add support to send http requests and parse http headers

Adriano Cordova
2024-11-12T02:49:47Z

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>
---

Changes in v3:
- Add a struct wget_http_info efi_wget_info for efi_net to pass to wget
when issuing wget requests, instead of using the old wget_info (see v2
of the series 'wget: Expose wget to applications').
- Let a pointer to the http status code be passed to efi_net_do_request
for it to fill it for the client after a request.

include/efi_loader.h | 13 ++++
lib/efi_loader/efi_net.c | 158 +++++++++++++++++++++++++++++++++++++++
2 files changed, 171 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index f49f8e6be0..4d05c08441 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,
+ 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_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..30234ae1c7 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>
@@ -34,6 +35,12 @@ static int rx_packet_num;
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.
@@ -1003,6 +1010,10 @@ out_of_resources:
return EFI_OUT_OF_RESOURCES;
}

+/**
+ * efi_net_set_dp() - set device path of efi net device
+ *
+ */
void efi_net_set_dp(const char *dev, const char *server)
{
if (!strcmp(dev, "Net"))
@@ -1011,6 +1022,10 @@ void efi_net_set_dp(const char *dev, const char *server)
net_dp = efi_dp_from_http(server);
}

+/**
+ * efi_net_set_dp() - get device path of efi net device
+ *
+ */
void efi_net_get_dp(void **dp)
{
if (!net_dp)
@@ -1019,6 +1034,10 @@ void efi_net_get_dp(void **dp)
*dp = efi_dp_dup(net_dp);
}

+/**
+ * efi_net_get_addr() - get IP address information
+ *
+ */
void efi_net_get_addr(struct efi_ipv4_address *ip,
struct efi_ipv4_address *mask,
struct efi_ipv4_address *gw)
@@ -1068,6 +1087,10 @@ void efi_net_get_addr(struct efi_ipv4_address *ip,
#endif
}

+/**
+ * efi_net_set_addr() - set IP address information
+ *
+ */
void efi_net_set_addr(struct efi_ipv4_address *ip,
struct efi_ipv4_address *mask,
struct efi_ipv4_address *gw)
@@ -1117,3 +1140,138 @@ void efi_net_set_addr(struct efi_ipv4_address *ip,
memcpy((void *)&net_netmask, (void *)mask, 4);
#endif
}
+
+/**
+ * efi_net_set_buffer() - allocate a buffer of min 64K
+ *
+ */
+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;
+
+ efi_wget_info.buffer_size = size;
+ //debug("efi_net: set buffer of size %lu at %lu\n", size, *buffer);
+ 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.
+ */
+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
+ *
+ */
+efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method, ulong *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 ? 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, (ulong)efi_wget_info.hdr_cont_len);
+ if (ret != EFI_SUCCESS)
+ goto out;
+ if (wget_request((ulong)*buffer, url, &efi_wget_info)) {
+ 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 = 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;
+}
--
2.43.0