efi_loader: device_path: add support for HTTP device path

Add efi_dp_from_http to form a device path from HTTP. The
device path is the concatenation of the device path returned
by efi_dp_from_ipv4 together with an URI node and an END node.

Signed-off-by: Adriano Cordova <adrianox@gmail.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

2 files changed, 65 insertions, 0 deletions

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 612bc42816b..96b204dfc31 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -872,6 +872,7 @@ struct efi_device_path *efi_dp_part_node(struct blk_desc *desc, int part);
 struct efi_device_path *efi_dp_from_file(const struct efi_device_path *dp,
 					 const char *path);
 struct efi_device_path *efi_dp_from_eth(void);
+struct efi_device_path *efi_dp_from_http(const char *server);
 struct efi_device_path *efi_dp_from_mem(uint32_t mem_type,
 					uint64_t start_address,
 					size_t size);
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 6fcbc91e0ba..a6d43006869 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -1021,6 +1021,70 @@ static struct efi_device_path *efi_dp_from_ipv4(struct efi_ipv4_address *ip,
 	return dp2;
 }
 
+/**
+ * efi_dp_from_http() - set device path from http
+ *
+ * Set the device path to an IPv4 path as provided by efi_dp_from_ipv4
+ * concatenated with a device path of subtype DEVICE_PATH_SUB_TYPE_MSG_URI,
+ * and an END node.
+ *
+ * @server:	URI of remote server
+ * Return:	pointer to HTTP device path, NULL on error
+ */
+struct efi_device_path *efi_dp_from_http(const char *server)
+{
+	struct efi_device_path *dp1, *dp2;
+	struct efi_device_path_uri *uridp;
+	efi_uintn_t uridp_len;
+	char *pos;
+	char tmp[128];
+	struct efi_ipv4_address ip;
+	struct efi_ipv4_address mask;
+
+	if ((server && strlen("http://") + strlen(server) + 1  > sizeof(tmp)) ||
+	    (!server && IS_ENABLED(CONFIG_NET_LWIP)))
+		return NULL;
+
+	efi_net_get_addr(&ip, &mask, NULL);
+
+	dp1 = efi_dp_from_ipv4(&ip, &mask, NULL);
+	if (!dp1)
+		return NULL;
+
+	strcpy(tmp, "http://");
+
+	if (server) {
+		strlcat(tmp, server, sizeof(tmp));
+#if !IS_ENABLED(CONFIG_NET_LWIP)
+	}
+	else {
+		ip_to_string(net_server_ip, tmp + strlen("http://"));
+#endif
+	}
+
+	uridp_len = sizeof(struct efi_device_path) + strlen(tmp) + 1;
+	uridp = efi_alloc(uridp_len + sizeof(END));
+	if (!uridp) {
+		log_err("Out of memory\n");
+		return NULL;
+	}
+	uridp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
+	uridp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_URI;
+	uridp->dp.length = uridp_len;
+	debug("device path: setting uri device path to %s\n", tmp);
+	memcpy(uridp->uri, tmp, strlen(tmp) + 1);
+
+	pos = (char *)uridp + uridp_len;
+	memcpy(pos, &END, sizeof(END));
+
+	dp2 = efi_dp_concat(dp1, (const struct efi_device_path *)uridp, 0);
+
+	efi_free_pool(uridp);
+	efi_free_pool(dp1);
+
+	return dp2;
+}
+
 /* Construct a device-path for memory-mapped image */
 struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 					uint64_t start_address,