Save list of DNS servers; do DNS lookup for hostnames

diff --git a/dnsresolv.inc b/dnsresolv.inc
index 23094d9..af48b74 100644 (file)
--- a/dnsresolv.inc
+++ b/dnsresolv.inc
@@ -28,7 +28,8 @@ DNS_MAX_SERVERS equ 4                 ; Max no of DNS servers
 
 ;
 ; Turn a string in DS:SI into a DNS "label set" in ES:DI.
-; On return, DI points to the first byte after the label set.
+; On return, DI points to the first byte after the label set,
+; and SI to the terminating byte.
 ;
 ; Assumes DS == ES.  Change references to [bx] to [es:bx] to remove
 ; that assumption.
@@ -45,12 +46,15 @@ dns_mangle:
                lodsb
                and al,al
                jz .endstring
+               cmp al,':'
+               jz .endstring
                cmp al,'.'
                je .isdot
                inc byte [bx]
                stosb
                jmp .getbyte
 .endstring:
+               dec si
                cmp byte [bx],0
                jz .done
                xor al,al
@@ -117,7 +121,7 @@ dns_skiplabel:
                ret
 
 ; Actual resolver function
-; Points to a null-terminated string in DS:SI
+; Points to a null-terminated or :-terminated string in DS:SI
 ; and returns the name in EAX if it exists and can be found.
 ; If EAX = 0 on exit, the lookup failed.
 

diff --git a/pxelinux.asm b/pxelinux.asm
index f99478e..5dde97b 100644 (file)
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -1484,10 +1484,29 @@ mangle_name:
                mov eax,[ServerIP]
                cmp word [si],'::'              ; Leading ::?
                je .gotprefix
+
+.more:
+               cmp word [si],'::'
+               je .here
+               cmp byte [si],0
+               jne .more
+               jmp .noip
+
+               ; We have a :: prefix of some sort, it could be either
+               ; a DNS name or a dot-quad IP address.  Try the dot-quad
+               ; first...
+.here:
+               pop si
+               push si
                call parse_dotquad
-               jc .noip
+               jc .notdq
                cmp word [si],'::'
                je .gotprefix
+.notdq:
+               call dns_resolv
+               cmp word [si],'::'
+               je .gotprefix
+
 .noip:
                pop si
                xor eax,eax
@@ -1512,6 +1531,7 @@ mangle_name:
                inc cx                          ; At least one null byte
                xor ax,ax                       ; Zero-fill name
                rep stosb                       ; Doesn't do anything if CX=0
+               pop bx
                ret                             ; Done
 
 ;
@@ -2022,6 +2042,7 @@ gendotquad:
 ; Netmask      - network mask
 ; Gateway      - default gateway router IP
 ; BootFile     - boot file name
+; DNSServers   - DNS server IPs
 ;
 ; This assumes the DHCP packet is in "trackbuf" and the length
 ; of the packet in in CX on entry.
@@ -2107,7 +2128,7 @@ parse_some_dhcp_options:
                sub cx,ax       ; Decrement bytes left counter
                jb .done        ; Malformed option: length > field size
 
-               cmp dl,dh       ; Is the option value 
+               cmp dl,dh       ; Is the option value valid?
                jb .opt_done
 
                cmp dl,1        ; SUBNET MASK option
@@ -2124,6 +2145,21 @@ parse_some_dhcp_options:
                jmp .opt_done
 .not_router:
 
+               cmp dl,6        ; DNS SERVERS option
+               jne .not_dns
+               pusha
+               shr cx,2
+               cmp cl,DNS_MAX_SERVERS
+               jna .oklen
+               mov cl,DNS_MAX_SERVERS
+.oklen:
+               mov di,DNSServers
+               rep movsd
+               mov [LastDNSServer],di
+               popa
+               jmp .opt_done
+.not_dns:
+
                cmp dl,43       ; VENDOR ENCAPSULATED option
                jne .not_vendor
                pusha