1 2# 3# This is an example that shows how to send ASCII formatted control 4# messages to a node using ngctl(8). 5# 6# What we will do here create a divert(4) tap. This simply dumps 7# out all packets diverted by some ipfw(8) divert rule to the console. 8# 9# Lines that begin with ``$'' (shell prompt) or ``+'' (ngctl prompt) 10# indicate user input 11# 12 13# First, start up ngctl in interactive mode: 14 15 $ ngctl 16 Available commands: 17 connect Connects hook <peerhook> of the node at <relpath> to <hook> 18 debug Get/set debugging verbosity level 19 help Show command summary or get more help on a specific command 20 list Show information about all nodes 21 mkpeer Create and connect a new node to the node at "path" 22 msg Send a netgraph control message to the node at "path" 23 name Assign name <name> to the node at <path> 24 read Read and execute commands from a file 25 rmhook Disconnect hook "hook" of the node at "path" 26 show Show information about the node at <path> 27 shutdown Shutdown the node at <path> 28 status Get human readable status information from the node at <path> 29 types Show information about all installed node types 30 quit Exit program 31 + 32 33# Now let's create a ng_ksocket(4) node, in the family PF_DIVERT, 34# of type SOCK_RAW: 35 36 + mkpeer ksocket foo divert/raw/0 37 38# Note that ``foo'' is the hook name on the socket node, which can be 39# anything. The ``inet/raw/divert'' is the hook name on the ksocket 40# node, which tells it what kind of socket to create. 41 42# Lets give our ksocket node a global name. How about ``fred'': 43 44 + name foo fred 45 46# Note that we used ngctl's ``name'' command to do this. However, 47# the following manually constructed netgraph message would have 48# accomplished the exact same thing: 49 50 + msg foo name { name="fred" } 51 52# Here we are using the ASCII <-> binary control message conversion 53# routines. ngctl does this for us automatically when we use the 54# ``msg'' command. 55 56# Now lets bind the socket associated with the ksocket node to a port 57# supplied by the system. We do this by sending the ksocket node a 58# ``bind'' control message. Again, ngctl does the conversion of the 59# control message from ASCII to binary behind the scenes. 60 61 + msg fred: bind inet/192.168.1.1 62 63# The ksocket accepts arbitrary sockaddr structures, but also has 64# special support for the PF_LOCAL and PF_INET protocol families. 65# That is why we can specify the struct sockaddr argument to the 66# ``bind'' command as ``inet/192.168.1.1'' (since we didn't specify 67# a port number, it's assumed to be zero). We could have also 68# relied on the generic sockaddr syntax and instead said this: 69 70 + msg fred: bind { family=2 len=16 data=[ 2=192 168 1 1 ] } 71 72# This is what you would have to do for protocol families other 73# that PF_INET and PF_LOCAL, at least until special handling for 74# new ones is added. 75 76# The reason for the ``2=192'' is to skip the two byte IP port number, 77# which causes it to be set to zero, the default value for integral 78# types when parsing. Now since we didn't ask for a specific port 79# number, we need to do a ``getname'' to see what port number we got: 80 81 + msg fred: getname 82 Rec'd response "getname" (5) from "fred:": 83 Args: inet/192.168.1.1:1029 84 85# As soon as we sent the message, we got back a response. Here 86# ngctl is telling us that it received a control message with the 87# NGF_RESP (response) flag set, the response was to a prior ``getname'' 88# control message, that the originator was the node addressable 89# as ``fred:''. The message arguments field is then displayed to 90# us in its ASCII form. In this case, what we get back is a struct 91# sockaddr, and there we see that our port number is 1029. 92 93# So now let's add the ipfw divert rule for whatever packets we 94# want to see. How about anything from 192.168.1.129. 95 96 + ^Z 97 Suspended 98 $ ipfw add 100 divert 1029 ip from 192.168.1.129 to any 99 00100 divert 1029 ip from 192.168.1.129 to any 100 $ fg 101 102# Now watch what happens when we try to ping from that machine: 103 104 + 105 Rec'd data packet on hook "foo": 106 0000: 45 00 00 3c 57 00 00 00 20 01 bf ee c0 a8 01 81 E..<W... ....... 107 0010: c0 a8 01 01 08 00 49 5c 03 00 01 00 61 62 63 64 ......I\....abcd 108 0020: 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 efghijklmnopqrst 109 0030: 75 76 77 61 62 63 64 65 66 67 68 69 uvwabcdefghi 110 + 111 Rec'd data packet on hook "foo": 112 0000: 45 00 00 3c 58 00 00 00 20 01 be ee c0 a8 01 81 E..<X... ....... 113 0010: c0 a8 01 01 08 00 48 5c 03 00 02 00 61 62 63 64 ......H\....abcd 114 0020: 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 efghijklmnopqrst 115 0030: 75 76 77 61 62 63 64 65 66 67 68 69 uvwabcdefghi 116 + 117 Rec'd data packet on hook "foo": 118 0000: 45 00 00 3c 59 00 00 00 20 01 bd ee c0 a8 01 81 E..<Y... ....... 119 0010: c0 a8 01 01 08 00 47 5c 03 00 03 00 61 62 63 64 ......G\....abcd 120 0020: 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 efghijklmnopqrst 121 0030: 75 76 77 61 62 63 64 65 66 67 68 69 uvwabcdefghi 122 + 123 124# So we're seeing the output from the ksocket socket appear on the ``foo'' 125# hook of ngctl's socket node. Since the packets are getting diverted, 126# the 192.168.1.129 machine doesn't see any response from us. 127 128# Of course, any type of socket can be used, even TCP: 129 130 + mkpeer ksocket bar inet/stream/tcp 131 + msg bar connect inet/192.168.1.33:13 132 ngctl: send msg: Operation now in progress 133 + 134 Rec'd data packet on hook "foo": 135 0000: 4d 6f 6e 20 4e 6f 76 20 32 39 20 31 37 3a 34 38 Mon Nov 29 17:48 136 0010: 3a 33 37 20 31 39 39 39 0d 0a :37 1999.. 137 + 138 139# Or, UNIX domain: 140 141 + mkpeer ksocket bar local/stream/0 142 + msg bar bind local/"/tmp/bar.socket" 143 + 144 145# Here's an example of a more complicated ASCII control message argument. 146# If you look in /sys/netgraph/ng_message.h, you will see that a node 147# responds to a NGM_LISTHOOKS with a struct hooklist, which contains 148# an array of struct linkinfo: 149# 150# /* Structure used for NGM_LISTHOOKS */ 151# struct linkinfo { 152# char ourhook[NG_HOOKSIZ]; /* hook name */ 153# char peerhook[NG_HOOKSIZ]; /* peer hook */ 154# struct nodeinfo nodeinfo; 155# }; 156# 157# struct hooklist { 158# struct nodeinfo nodeinfo; /* node information */ 159# struct linkinfo link[0]; /* info about each hook */ 160# }; 161# 162# By sending a node the ``listhooks'' command using ngctl, we can see 163# this structure in ASCII form (lines wrapped for readability): 164 165 + msg bar bind local/"/tmp/bar.socket" 166 + msg bar listhooks 167 Rec'd response "listhooks" (7) from "bar": 168 Args: { nodeinfo={ type="ksocket" id=9 hooks=1 } 169 linkinfo=[ { ourhook="local/stream/0" peerhook="bar" 170 nodeinfo={ name="ngctl1327" type="socket" id=8 hooks=1 } } ] } 171 172 173