IP

[fpgaboy.git] / ethernet.asm

diff --git a/ethernet.asm b/ethernet.asm
index 5e49ef62f3b564dd4d9c67aa6537c7dbfcb30176..8fb4fed1fd8d3da53dedbb15ec55ec270e19b0c5 100644 (file)
--- a/ethernet.asm
+++ b/ethernet.asm
@@ -277,6 +277,131 @@ arp_input:
        ret
 
 ip_input:
+       ; check for ipv4
+       ld a, [hl]
+       ld c, a
+       and $F0
+       swap a
+       sub $04
+       jr z, .ip_isv4
+       PUTSIL "ip_input: not ipv4 -- fuck off"
+       ret
+.ip_isv4
+       ; get length
+       ld a, c
+       and $0F
+       sla a
+       ld c, a
+       sla a
+       sub $14
+       ld b, a
+       push bc
+
+       ; check checksum
+       xor a
+       ld d, a
+       ld e, a
+       push hl
+.ip_cksumloop:
+       ld a, [hli]
+       ld b, a
+       ld a, [hli]
+       add e
+       ld e, a
+       ld a, b
+       add d
+       ld d, a
+       jr nc, .ip_noinc
+       inc de
+.ip_noinc:
+       dec c
+       jr nz, .ip_cksumloop
+
+       ; checksum ok
+       pop hl
+       ld a, d
+       or e
+       jr z, .ip_cksumgood
+       ld a, d
+       and e
+       cpl
+       or a
+       jr z, .ip_cksumgood
+       PUTSIL "ip_input: checksum fail -- bailing"
+       pop hl
+       ret
+.ip_cksumgood:
+       PUTSIL "ip_input: checksum good"
+       ld b, $00
+       ld c, $0C
+       add hl, bc
+       ld c, $04
+
+       ; print source IP
+       PUTSI "ip_input: this packet is from 0x"
+.ip_get_srcip:
+       ld a, [hli]
+       PUTHEX a
+       dec c
+       jr nz, .ip_get_srcip
+       PUTSIL "."
+
+       ; check dest IP
+       ld d, myIP >> 8
+       ld e, myIP & $FF
+       ld c, $04
+.ip_chkip:
+       ld b, [hl]
+       inc hl
+       ld a, [de]
+       inc de
+       cp b
+       jr nz, .ip_ipfail
+       dec c
+       jr nz, .ip_chkip
+
+       PUTSIL "ip_input: wheeeeeeeeeeeeeeee"
+       ; get protocol in A
+       ld d, $FF
+       ld e, -$0B
+       add hl, de
+       ld a, [hl]
+       ld d, $00
+       ld e, $0B
+       add hl, de
+
+       ; make hl point at beginning of data
+       pop bc
+       ld c, b
+       ld b, $00
+       add hl, bc
+
+       ; ok, pass it off to something else
+       cp $01
+       jr z, .ip_icmp
+       cp $11
+       jr z, .ip_udp
+       ret
+
+.ip_icmp:
+       call icmp_input
+       ret
+
+.ip_udp:
+       call udp_input
+       ret
+
+.ip_ipfail:
+       PUTSIL "ip_input: this packet is not to our IP address. Bailing."
+       pop hl
+       ret
+
+icmp_input:
+       PUTSIL "icmp_input: too lazy to parse -- fuck off"
+       ret
+
+udp_input:
+       PUTSIL "udp_input: too lazy to parse -- fuck off"
        ret
 
 packet_send: