forked from KolibriOS/kolibrios
Updates in NET branch:
- Added RST packet handling code - Added SOCKET_isconnected - Added ACK handeling in syn rcvd state (for passive open) git-svn-id: svn://kolibrios.org@1831 a494cfbc-eb01-0410-851d-a64ba20cac60
This commit is contained in:
parent
0d53bac040
commit
36e43113ac
@ -501,7 +501,7 @@ align 4
|
||||
@@:
|
||||
|
||||
mov [eax + TCP_SOCKET.timer_persist], 0
|
||||
mov [eax + TCP_SOCKET.t_state], TCB_SYN_SENT
|
||||
mov [eax + TCP_SOCKET.t_state], TCPS_SYN_SENT
|
||||
push [TCP_sequence_num]
|
||||
add [TCP_sequence_num], 6400
|
||||
pop [eax + TCP_SOCKET.ISS]
|
||||
@ -585,7 +585,7 @@ SOCKET_listen:
|
||||
|
||||
mov [eax + SOCKET.backlog], dx
|
||||
or [eax + SOCKET.options], SO_ACCEPTCON
|
||||
mov [eax + TCP_SOCKET.t_state], TCB_LISTEN
|
||||
mov [eax + TCP_SOCKET.t_state], TCPS_LISTEN
|
||||
|
||||
push eax
|
||||
init_queue (eax + SOCKET_QUEUE_LOCATION) ; Set up sockets queue
|
||||
@ -666,7 +666,7 @@ SOCKET_close:
|
||||
jmp s_error
|
||||
|
||||
.tcp:
|
||||
cmp [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED ; state must be LISTEN, SYN_SENT or CLOSED
|
||||
cmp [eax + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED ; state must be LISTEN, SYN_SENT or CLOSED
|
||||
jl .free
|
||||
|
||||
call TCP_output
|
||||
@ -849,7 +849,7 @@ SOCKET_send_icmp:
|
||||
;
|
||||
; At moment, uses only pseudo-optname -2 for get last_ack_number for TCP.
|
||||
; TODO: find best way to notify that send()'ed data were acknowledged
|
||||
; Also pseudo-optname -3 is valid and returns socket state, one of TCB_*.
|
||||
; Also pseudo-optname -3 is valid and returns socket state, one of TCPS_*.
|
||||
;
|
||||
;-----------------------------------------------------------------
|
||||
align 4
|
||||
@ -1738,3 +1738,23 @@ align 4
|
||||
SOCKET_cant_recv_more:
|
||||
|
||||
ret
|
||||
|
||||
|
||||
|
||||
;-----------------------------------------------------------------
|
||||
;
|
||||
; SOCKET_is_connected
|
||||
;
|
||||
; IN: eax = socket ptr
|
||||
; OUT: /
|
||||
;
|
||||
;-----------------------------------------------------------------
|
||||
|
||||
align 4
|
||||
SOCKET_is_connected:
|
||||
|
||||
|
||||
and [eax + SOCKET.options], not (SS_ISCONNECTING + SS_ISDISCONNECTING + SS_ISCONFIRMING)
|
||||
or [eax + SOCKET.options], SS_ISCONNECTED
|
||||
|
||||
jmp SOCKET_notify_owner
|
@ -17,17 +17,17 @@
|
||||
$Revision$
|
||||
|
||||
; Socket states
|
||||
TCB_CLOSED equ 0
|
||||
TCB_LISTEN equ 1
|
||||
TCB_SYN_SENT equ 2
|
||||
TCB_SYN_RECEIVED equ 3
|
||||
TCB_ESTABLISHED equ 4
|
||||
TCB_CLOSE_WAIT equ 5
|
||||
TCB_FIN_WAIT_1 equ 6
|
||||
TCB_CLOSING equ 7
|
||||
TCB_LAST_ACK equ 8
|
||||
TCB_FIN_WAIT_2 equ 9
|
||||
TCB_TIMED_WAIT equ 10
|
||||
TCPS_CLOSED equ 0
|
||||
TCPS_LISTEN equ 1
|
||||
TCPS_SYN_SENT equ 2
|
||||
TCPS_SYN_RECEIVED equ 3
|
||||
TCPS_ESTABLISHED equ 4
|
||||
TCPS_CLOSE_WAIT equ 5
|
||||
TCPS_FIN_WAIT_1 equ 6
|
||||
TCPS_CLOSING equ 7
|
||||
TCPS_LAST_ACK equ 8
|
||||
TCPS_FIN_WAIT_2 equ 9
|
||||
TCPS_TIMED_WAIT equ 10
|
||||
|
||||
; Socket Flags
|
||||
TF_ACKNOW equ 1 shl 0 ; ack peer immediately
|
||||
|
@ -105,7 +105,7 @@ TCP_input:
|
||||
ntohw [edx + TCP_segment.DestinationPort]
|
||||
|
||||
;------------------------------------------------------------
|
||||
; Next thing to do is find the TCB (thus, the socket pointer)
|
||||
; Next thing to do is find the TCPS (thus, the socket pointer)
|
||||
|
||||
; IP Packet TCP Destination Port = local Port
|
||||
; (IP Packet SenderAddress = Remote IP) OR (Remote IP = 0)
|
||||
@ -148,7 +148,7 @@ TCP_input:
|
||||
;----------------------------
|
||||
; Check if socket isnt closed
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSED
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSED
|
||||
je .drop_not_locked
|
||||
|
||||
;----------------
|
||||
@ -193,7 +193,7 @@ TCP_input:
|
||||
push [edx - IPv4_Packet.DataOrOptional + IPv4_Packet.SourceAddress] ;;; FIXME
|
||||
pop [eax + IP_SOCKET.RemoteIP]
|
||||
|
||||
mov [eax + TCP_SOCKET.t_state], TCB_LISTEN
|
||||
mov [eax + TCP_SOCKET.t_state], TCPS_LISTEN
|
||||
|
||||
jmp .not_uni_xfer
|
||||
|
||||
@ -213,7 +213,7 @@ TCP_input:
|
||||
|
||||
DEBUGF 1,"Segment has options\n"
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_LISTEN ; no options when in listen state
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_LISTEN ; no options when in listen state
|
||||
jz .not_uni_xfer ; also no header prediction
|
||||
|
||||
lea edi, [edx + TCP_segment.Data]
|
||||
@ -310,7 +310,7 @@ TCP_input:
|
||||
; - If the length is not 0 and the ACK didn't move, we're the receiver side of the transfer.
|
||||
; If the packets are in order (data queue is empty), add the data to the socket buffer and request a delayed ACK
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED
|
||||
jnz .not_uni_xfer
|
||||
|
||||
test [edx + TCP_segment.Flags], TH_SYN + TH_FIN + TH_RST + TH_URG
|
||||
@ -438,10 +438,10 @@ TCP_input:
|
||||
|
||||
;;;; TODO: 444
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_LISTEN
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_LISTEN
|
||||
je .LISTEN
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_SENT
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_SYN_SENT
|
||||
je .SYN_SENT
|
||||
|
||||
jmp .NOT_LISTEN_OR_SYN_SENT
|
||||
@ -481,7 +481,7 @@ align 4
|
||||
TCP_sendseqinit eax
|
||||
TCP_rcvseqinit eax
|
||||
|
||||
mov [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
|
||||
mov [eax + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED
|
||||
mov [eax + TCP_SOCKET.t_flags], TF_ACKNOW
|
||||
mov [eax + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval ;;;; macro
|
||||
|
||||
@ -578,7 +578,7 @@ align 4
|
||||
|
||||
mov [ebx + SOCKET.state],1 ;;;; FIXME
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED
|
||||
|
||||
;;; TODO: check if we should scale the connection (567-572)
|
||||
;;; TODO: update RTT estimators
|
||||
@ -589,7 +589,7 @@ align 4
|
||||
|
||||
DEBUGF 1,"TCP: simultaneous open\n"
|
||||
; We have received a syn but no ACK, so we are having a simultaneous open..
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED
|
||||
|
||||
|
||||
|
||||
@ -747,7 +747,7 @@ align 4
|
||||
cmp [ebx + SOCKET.PID], 0
|
||||
jg @f
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSE_WAIT
|
||||
jle @f
|
||||
|
||||
test ecx, ecx
|
||||
@ -811,44 +811,43 @@ align 4
|
||||
jmp dword [eax + .rst_sw_list]
|
||||
|
||||
.rst_sw_list:
|
||||
dd .rst_skip ;TCB_CLOSED
|
||||
dd .rst_skip ;TCB_LISTEN
|
||||
dd .rst_skip ;TCB_SYN_SENT
|
||||
dd .econnrefused ;TCB_SYN_RECEIVED
|
||||
dd .econnreset ;TCB_ESTABLISHED
|
||||
dd .econnreset ;TCB_CLOSE_WAIT
|
||||
dd .econnreset ;TCB_FIN_WAIT_1
|
||||
dd .rst_close ;TCB_CLOSING
|
||||
dd .rst_close ;TCB_LAST_ACK
|
||||
dd .econnreset ;TCB_FIN_WAIT_2
|
||||
dd .rst_close ;TCB_TIMED_WAIT
|
||||
dd .rst_skip ;TCPS_CLOSED
|
||||
dd .rst_skip ;TCPS_LISTEN
|
||||
dd .rst_skip ;TCPS_SYN_SENT
|
||||
dd .econnrefused ;TCPS_SYN_RECEIVED
|
||||
dd .econnreset ;TCPS_ESTABLISHED
|
||||
dd .econnreset ;TCPS_CLOSE_WAIT
|
||||
dd .econnreset ;TCPS_FIN_WAIT_1
|
||||
dd .rst_close ;TCPS_CLOSING
|
||||
dd .rst_close ;TCPS_LAST_ACK
|
||||
dd .econnreset ;TCPS_FIN_WAIT_2
|
||||
dd .rst_close ;TCPS_TIMED_WAIT
|
||||
|
||||
.econnrefused:
|
||||
|
||||
DEBUGF 1,"Connection refused"
|
||||
|
||||
;;; TODO: debug info
|
||||
|
||||
mov [ebx + SOCKET.errorcode], ECONNREFUSED
|
||||
jmp .close
|
||||
|
||||
.econnreset:
|
||||
|
||||
DEBUGF 1,"Connection reset"
|
||||
|
||||
;;; TODO: debug info
|
||||
mov [ebx + SOCKET.errorcode], ECONNRESET
|
||||
|
||||
.close:
|
||||
|
||||
DEBUGF 1,"Closing connection"
|
||||
|
||||
;;; update stats
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSED
|
||||
;;; TODO: update stats
|
||||
mov eax, ebx
|
||||
call TCP_close
|
||||
jmp .drop
|
||||
|
||||
.rst_close:
|
||||
|
||||
DEBUGF 1,"Closing with reset\n"
|
||||
|
||||
;;; Close the socket
|
||||
|
||||
mov eax, ebx
|
||||
call TCP_close
|
||||
jmp .drop
|
||||
|
||||
|
||||
@ -866,9 +865,9 @@ align 4
|
||||
test [edx + TCP_segment.Flags], TH_SYN
|
||||
jz @f
|
||||
|
||||
mov eax, ebx
|
||||
mov ebx, ECONNRESET
|
||||
call TCP_drop
|
||||
|
||||
jmp .drop_with_reset
|
||||
|
||||
test [edx + TCP_segment.Flags], TH_ACK
|
||||
@ -884,12 +883,39 @@ align 4
|
||||
;---------------
|
||||
; ACK processing
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED
|
||||
jnz .no_syn_rcv
|
||||
|
||||
DEBUGF 1,"TCP state = syn received\n"
|
||||
|
||||
;;;;; 801-815
|
||||
mov eax, [edx + TCP_segment.AckNumber]
|
||||
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
|
||||
jg .drop_with_reset
|
||||
|
||||
cmp [ebx + TCP_SOCKET.SND_MAX], eax
|
||||
jg .drop_with_reset
|
||||
;;; update stats
|
||||
mov eax, ebx
|
||||
call SOCKET_is_connected
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED
|
||||
|
||||
; Do window scaling?
|
||||
|
||||
test [ebx + TCP_SOCKET.t_flags], TF_RCVD_SCALE
|
||||
jz @f
|
||||
test [ebx + TCP_SOCKET.t_flags], TF_REQ_SCALE
|
||||
jz @f
|
||||
|
||||
;;; 810-811
|
||||
|
||||
@@:
|
||||
|
||||
;;; 813 ?
|
||||
|
||||
mov eax, [edx + TCP_segment.SequenceNumber]
|
||||
dec eax
|
||||
mov [ebx + TCP_SOCKET.SND_WL1], eax
|
||||
jmp .not_dup_ack
|
||||
|
||||
.no_syn_rcv:
|
||||
|
||||
@ -1095,7 +1121,7 @@ align 4
|
||||
mov eax, ebx
|
||||
call SOCKET_notify_owner
|
||||
|
||||
; Update TCB
|
||||
; Update TCPS
|
||||
|
||||
mov eax, [edx + TCP_segment.AckNumber]
|
||||
mov [ebx + TCP_SOCKET.SND_UNA], eax
|
||||
@ -1118,17 +1144,17 @@ align 4
|
||||
jmp dword [eax*4 + .ACK_sw_list]
|
||||
|
||||
.ACK_sw_list:
|
||||
dd .ack_processed ;TCB_CLOSED
|
||||
dd .ack_processed ;TCB_LISTEN
|
||||
dd .ack_processed ;TCB_SYN_SENT
|
||||
dd .ack_processed ;TCB_SYN_RECEIVED
|
||||
dd .ack_processed ;TCB_ESTABLISHED
|
||||
dd .ack_processed ;TCB_CLOSE_WAIT
|
||||
dd .ack_fw1 ;TCB_FIN_WAIT_1
|
||||
dd .ack_c ;TCB_CLOSING
|
||||
dd .ack_la ;TCB_LAST_ACK
|
||||
dd .ack_processed ;TCB_FIN_WAIT_2
|
||||
dd .ack_tw ;TCB_TIMED_WAIT
|
||||
dd .ack_processed ;TCPS_CLOSED
|
||||
dd .ack_processed ;TCPS_LISTEN
|
||||
dd .ack_processed ;TCPS_SYN_SENT
|
||||
dd .ack_processed ;TCPS_SYN_RECEIVED
|
||||
dd .ack_processed ;TCPS_ESTABLISHED
|
||||
dd .ack_processed ;TCPS_CLOSE_WAIT
|
||||
dd .ack_fw1 ;TCPS_FIN_WAIT_1
|
||||
dd .ack_c ;TCPS_CLOSING
|
||||
dd .ack_la ;TCPS_LAST_ACK
|
||||
dd .ack_processed ;TCPS_FIN_WAIT_2
|
||||
dd .ack_tw ;TCPS_TIMED_WAIT
|
||||
|
||||
|
||||
.ack_fw1:
|
||||
@ -1141,14 +1167,14 @@ align 4
|
||||
;;; mov [ebx + TCP_SOCKET.timer_timed_wait], TCP_time_max_idle
|
||||
@@:
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_2
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_FIN_WAIT_2
|
||||
jmp .ack_processed
|
||||
|
||||
|
||||
.ack_c:
|
||||
jz .ack_processed
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT
|
||||
mov eax, ebx
|
||||
call TCP_cancel_timers
|
||||
mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL
|
||||
@ -1262,7 +1288,7 @@ align 4
|
||||
cmp [edx + TCP_segment.UrgentPointer], 0
|
||||
jz .not_urgent
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT
|
||||
je .not_urgent
|
||||
|
||||
; Ignore bogus urgent offsets
|
||||
@ -1301,7 +1327,7 @@ align 4
|
||||
test [edx + TCP_segment.Flags], TH_FIN
|
||||
jnz .process_fin
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_1
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_FIN_WAIT_1
|
||||
jge .dont_do_data
|
||||
|
||||
test ecx, ecx
|
||||
@ -1344,11 +1370,11 @@ align 4
|
||||
|
||||
DEBUGF 1,"Processing FIN\n"
|
||||
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSE_WAIT
|
||||
je .not_first_fin
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSING
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSING
|
||||
je .not_first_fin
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_2
|
||||
cmp [ebx + TCP_SOCKET.t_state], TCPS_FIN_WAIT_2
|
||||
je .not_first_fin
|
||||
|
||||
DEBUGF 1,"First FIN for this connection\n"
|
||||
@ -1365,31 +1391,31 @@ align 4
|
||||
jmp dword [eax + .FIN_sw_list]
|
||||
|
||||
.FIN_sw_list:
|
||||
dd .no_fin ;TCB_CLOSED
|
||||
dd .no_fin ;TCB_LISTEN
|
||||
dd .no_fin ;TCB_SYN_SENT
|
||||
dd .fin_syn_est ;TCB_SYN_RECEIVED
|
||||
dd .fin_syn_est ;TCB_ESTABLISHED
|
||||
dd .no_fin ;TCB_CLOSE_WAIT
|
||||
dd .fin_wait1 ;TCB_FIN_WAIT_1
|
||||
dd .no_fin ;TCB_CLOSING
|
||||
dd .no_fin ;TCB_LAST_ACK
|
||||
dd .fin_wait2 ;TCB_FIN_WAIT_2
|
||||
dd .fin_timed ;TCB_TIMED_WAIT
|
||||
dd .no_fin ;TCPS_CLOSED
|
||||
dd .no_fin ;TCPS_LISTEN
|
||||
dd .no_fin ;TCPS_SYN_SENT
|
||||
dd .fin_syn_est ;TCPS_SYN_RECEIVED
|
||||
dd .fin_syn_est ;TCPS_ESTABLISHED
|
||||
dd .no_fin ;TCPS_CLOSE_WAIT
|
||||
dd .fin_wait1 ;TCPS_FIN_WAIT_1
|
||||
dd .no_fin ;TCPS_CLOSING
|
||||
dd .no_fin ;TCPS_LAST_ACK
|
||||
dd .fin_wait2 ;TCPS_FIN_WAIT_2
|
||||
dd .fin_timed ;TCPS_TIMED_WAIT
|
||||
|
||||
.fin_syn_est:
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSE_WAIT
|
||||
jmp .no_fin
|
||||
|
||||
.fin_wait1:
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_CLOSING
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSING
|
||||
jmp .no_fin
|
||||
|
||||
.fin_wait2:
|
||||
|
||||
mov [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
|
||||
mov [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT
|
||||
mov eax, ebx
|
||||
call TCP_cancel_timers
|
||||
mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL
|
||||
|
@ -130,10 +130,10 @@ TCP_drop:
|
||||
|
||||
DEBUGF 1,"TCP_drop\n"
|
||||
|
||||
cmp [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
|
||||
cmp [eax + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED
|
||||
jl .no_syn_received
|
||||
|
||||
mov [eax + TCP_SOCKET.t_state], TCB_CLOSED
|
||||
mov [eax + TCP_SOCKET.t_state], TCPS_CLOSED
|
||||
|
||||
call TCP_output
|
||||
|
||||
@ -209,17 +209,17 @@ TCP_outflags:
|
||||
|
||||
.flaglist:
|
||||
|
||||
db TH_RST + TH_ACK ; TCB_CLOSED
|
||||
db 0 ; TCB_LISTEN
|
||||
db TH_SYN ; TCB_SYN_SENT
|
||||
db TH_SYN + TH_ACK ; TCB_SYN_RECEIVED
|
||||
db TH_ACK ; TCB_ESTABLISHED
|
||||
db TH_ACK ; TCB_CLOSE_WAIT
|
||||
db TH_SYN + TH_ACK ; TCB_FIN_WAIT_1
|
||||
db TH_SYN + TH_ACK ; TCB_CLOSING
|
||||
db TH_SYN + TH_ACK ; TCB_LAST_ACK
|
||||
db TH_ACK ; TCB_FIN_WAIT_2
|
||||
db TH_ACK ; TCB_TIMED_WAIT
|
||||
db TH_RST + TH_ACK ; TCPS_CLOSED
|
||||
db 0 ; TCPS_LISTEN
|
||||
db TH_SYN ; TCPS_SYN_SENT
|
||||
db TH_SYN + TH_ACK ; TCPS_SYN_RECEIVED
|
||||
db TH_ACK ; TCPS_ESTABLISHED
|
||||
db TH_ACK ; TCPS_CLOSE_WAIT
|
||||
db TH_SYN + TH_ACK ; TCPS_FIN_WAIT_1
|
||||
db TH_SYN + TH_ACK ; TCPS_CLOSING
|
||||
db TH_SYN + TH_ACK ; TCPS_LAST_ACK
|
||||
db TH_ACK ; TCPS_FIN_WAIT_2
|
||||
db TH_ACK ; TCPS_TIMED_WAIT
|
||||
|
||||
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user