pxe: add stivale2 pxe server info tag

STIVALE2.md

@@ -456,6 +456,17 @@ struct stivale2_smp_info {
 } __attribute__((packed));
 ```
 
+#### PXE server info structure tag
+
+This tag reports that the kernel has been booted via PXE, and reports the server ip that it was booted from.
+
+```c
+struct stivale2_struct_tag_pxe_server_info {
+    struct stivale2_tag tag;     // Identifier: 0x29d1e96239247032
+    uint32_t server_ip;          // Server ip in network byte order
+} __attribute__((packed));
+```
+
 #### MMIO32 UART tag
 
 This tag reports that there is a memory mapped UART port and its address. To write to this port, write the character, zero extended to a 32 bit unsigned integer to the address provided.

stage2/main.c

@@ -80,7 +80,7 @@ void entry(uint8_t _boot_drive, int pxe_boot) {
     if (!strcmp(proto, "stivale")) {
         stivale_load(config, cmdline);
     } else if (!strcmp(proto, "stivale2")) {
-        stivale2_load(config, cmdline);
+        stivale2_load(config, cmdline, pxe_boot);
     } else if (!strcmp(proto, "linux")) {
         linux_load(config, cmdline);
     } else if (!strcmp(proto, "chainload")) {

stage2/protos/stivale2.c

@@ -23,6 +23,7 @@
 #include <fs/file.h>
 #include <mm/pmm.h>
 #include <stivale/stivale2.h>
+#include <pxe/tftp.h>
 
 #define KASLR_SLIDE_BITMASK 0x03FFFF000u
 
@@ -50,7 +51,7 @@ static void append_tag(struct stivale2_struct *s, struct stivale2_tag *tag) {
     s->tags   = (uint64_t)(size_t)tag;
 }
 
-void stivale2_load(char *config, char *cmdline) {
+void stivale2_load(char *config, char *cmdline, bool pxe) {
     struct file_handle *kernel = conv_mem_alloc(sizeof(struct file_handle));
 
     char *kernel_path = config_get_value(config, 0, "KERNEL_PATH");
@@ -352,6 +353,15 @@ void stivale2_load(char *config, char *cmdline) {
     append_tag(&stivale2_struct, (struct stivale2_tag *)tag);
     }
 
+    {
+        if (pxe) {
+            struct stivale2_struct_tag_pxe_server_info *tag = conv_mem_alloc(sizeof(struct stivale2_struct_tag_pxe_server_info));
+            tag->tag.identifier = STIVALE2_STRUCT_TAG_PXE_SERVER_INFO;
+            tag->server_ip = get_boot_server_info();
+            append_tag(&stivale2_struct, (struct stivale2_tag *)tag);
+        }
+    }
+
     stivale_spinup(bits, level5pg && level5pg_requested, pagemap,
                    entry_point, &stivale2_struct, stivale2_hdr.stack);
 }

stage2/protos/stivale2.h

@@ -1,6 +1,6 @@
 #ifndef __PROTOS__STIVALE2_H__
 #define __PROTOS__STIVALE2_H__
 
-void stivale2_load(char *config, char *cmdline);
+void stivale2_load(char *config, char *cmdline, bool pxe);
 
 #endif

stage2/pxe/tftp.c

@@ -6,7 +6,15 @@
 #include <mm/pmm.h>
 #include <lib/blib.h>
 
-int tftp_open(struct tftp_file_handle* handle, uint32_t server_ip, uint16_t server_port, const char* name) {
+uint32_t get_boot_server_info() {
+    struct pxenv_get_cached_info cachedinfo = { 0 };
+    cachedinfo.packet_type = 2;
+    pxe_call(PXENV_GET_CACHED_INFO, ((uint16_t)rm_seg(&cachedinfo)), (uint16_t)rm_off(&cachedinfo));
+    struct bootph *ph = (struct bootph*)(void *) (((((uint32_t)cachedinfo.buffer) >> 16) << 4) + (((uint32_t)cachedinfo.buffer) & 0xFFFF));
+    return ph->sip;
+}
+
+int tftp_open(struct tftp_file_handle *handle, uint32_t server_ip, uint16_t server_port, const char *name) {
     int ret = 0;
     if (!server_ip) {
         struct pxenv_get_cached_info cachedinfo = { 0 };

stage2/pxe/tftp.h

@@ -47,5 +47,6 @@ struct pxenv_get_file_size {
 //server_ip and server_port can be 0 for default
 int tftp_open(struct tftp_file_handle* handle, uint32_t server_ip, uint16_t server_port, const char* name);
 int tftp_read(void *fd, void *buf, uint64_t loc, uint64_t count);
+uint32_t get_boot_server_info();
 
 #endif

stivale/stivale2.h

@@ -159,4 +159,11 @@ struct stivale2_struct_tag_smp {
     struct stivale2_smp_info smp_info[];
 } __attribute__((packed));
 
+#define STIVALE2_STRUCT_TAG_PXE_SERVER_INFO 0x29d1e96239247032
+
+struct stivale2_struct_tag_pxe_server_info {
+    struct stivale2_tag tag;
+    uint32_t server_ip;
+} __attribute__((packed));
+
 #endif