.\" $Id: tsig.3,v 8.2 1999/01/08 18:54:28 vixie Exp $
.\"
.\"Copyright (c) 1995-1999 by Internet Software Consortium
.\"
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.\"OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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.\"SOFTWARE.
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.Dd January 1, 1996
.Os BSD 4
.Dt TSIG 2
.Sh NAME
.Nm ns_sign ,
.Nm ns_sign_tcp ,
.Nm ns_sign_tcp_init ,
.Nm ns_verify ,
.Nm ns_verify_tcp ,
.Nm ns_verify_tcp_init ,
.Nm ns_find_tsig
.Nd TSIG system
.Sh SYNOPSIS
.Ft int
.Fo ns_sign
.Fa "u_char *msg"
.Fa "int *msglen"
.Fa "int msgsize"
.Fa "int error"
.Fa "void *k"
.Fa "const u_char *querysig"
.Fa "int querysiglen"
.Fa "u_char *sig"
.Fa "int *siglen"
.Fa "time_t in_timesigned"
.Fc
.Ft int
.Fn ns_sign_tcp "u_char *msg" "int *msglen" "int msgsize" "int error" \
    "ns_tcp_tsig_state *state" "int done"
.Ft int
.Fn ns_sign_tcp_init "void *k" "const u_char *querysig" "int querysiglen" \
    "ns_tcp_tsig_state *state"
.Ft int
.Fo ns_verify
.Fa "u_char *msg"
.Fa "int *msglen"
.Fa "void *k"
.Fa "const u_char *querysig"
.Fa "int querysiglen"
.Fa "u_char *sig"
.Fa "int *siglen"
.Fa "time_t in_timesigned"
.Fa "int nostrip"
.Fc
.Ft int
.Fn ns_verify_tcp "u_char *msg" "int *msglen" "ns_tcp_tsig_state *state" \
    "int required"
.Ft int
.Fn ns_verify_tcp_init "void *k" "const u_char *querysig" "int querysiglen" \
    "ns_tcp_tsig_state *state"
.Ft u_char *
.Fn ns_find_tsig "u_char *msg" "u_char *eom"
.Sh DESCRIPTION
The TSIG routines are used to implement transaction/request security of
DNS messages.
.Pp
.Fn ns_sign
and
.Fn ns_verify
are the basic routines.
.Fn ns_sign_tcp
and
.Fn ns_verify_tcp
are used to sign/verify TCP messages that may be split into multiple packets,
such as zone transfers, and
.Fn ns_sign_tcp_init,
.Fn ns_verify_tcp_init
initialize the state structure necessary for TCP operations.
.Fn ns_find_tsig
locates the TSIG record in a message, if one is present.
.Pp
.Fn ns_sign
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv msg
the incoming DNS message, which will be modified
.It Dv msglen
the length of the DNS message, on input and output
.It Dv msgsize
the size of the buffer containing the DNS message on input
.It Dv error
the value to be placed in the TSIG error field
.It Dv key
the (DST_KEY *) to sign the data
.It Dv querysig
for a response, the signature contained in the query
.It Dv querysiglen
the length of the query signature
.It Dv sig
a buffer to be filled with the generated signature
.It Dv siglen
the length of the signature buffer on input, the signature length on output
.El
.Pp
.Fn ns_sign_tcp
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv msg
the incoming DNS message, which will be modified
.It Dv msglen
the length of the DNS message, on input and output
.It Dv msgsize
the size of the buffer containing the DNS message on input
.It Dv error
the value to be placed in the TSIG error field
.It Dv state
the state of the operation
.It Dv done
non-zero value signifies that this is the last packet
.El
.Pp
.Fn ns_sign_tcp_init
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv k
the (DST_KEY *) to sign the data
.It Dv querysig
for a response, the signature contained in the query
.It Dv querysiglen
the length of the query signature
.It Dv state
the state of the operation, which this initializes
.El
.Pp
.Fn ns_verify
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv msg
the incoming DNS message, which will be modified
.It Dv msglen
the length of the DNS message, on input and output
.It Dv key
the (DST_KEY *) to sign the data
.It Dv querysig
for a response, the signature contained in the query
.It Dv querysiglen
the length of the query signature
.It Dv sig
a buffer to be filled with the signature contained
.It Dv siglen
the length of the signature buffer on input, the signature length on output
.It Dv nostrip
non-zero value means that the TSIG is left intact
.El
.Pp
.Fn ns_verify_tcp
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv msg
the incoming DNS message, which will be modified
.It Dv msglen
the length of the DNS message, on input and output
.It Dv state
the state of the operation
.It Dv required
non-zero value signifies that a TSIG record must be present at this step
.El
.Pp
.Fn ns_verify_tcp_init
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv k
the (DST_KEY *) to verify the data
.It Dv querysig
for a response, the signature contained in the query
.It Dv querysiglen
the length of the query signature
.It Dv state
the state of the operation, which this initializes
.El
.Pp
.Fn ns_find_tsig
.Bl -tag -width "in_timesigned" -compact -offset indent
.It Dv msg
the incoming DNS message
.It Dv msglen
the length of the DNS message
.El
.Sh RETURN VALUES
.Fn ns_find_tsig
returns a pointer to the TSIG record if one is found, and NULL otherwise.
.Pp
All other routines return 0 on success, modifying arguments when necessary.
.Pp
.Fn ns_sign
and
.Fn ns_sign_tcp
return the following errors:
.Bl -tag -width "NS_TSIG_ERROR_NO_SPACE" -compact -offset indent
.It Dv (-1)
bad input data
.It Dv (-ns_r_badkey)
The key was invalid, or the signing failed
.It Dv NS_TSIG_ERROR_NO_SPACE
the message buffer is too small.
.El
.Pp
.Fn ns_verify
and
.Fn ns_verify_tcp
return the following errors:
.Bl -tag -width "NS_TSIG_ERROR_NO_SPACE" -compact -offset indent
.It Dv (-1)
bad input data
.It Dv NS_TSIG_ERROR_FORMERR
The message is malformed
.It Dv NS_TSIG_ERROR_NO_TSIG
The message does not contain a TSIG record
.It Dv NS_TSIG_ERROR_ID_MISMATCH
The TSIG original ID field does not match the message ID
.It Dv (-ns_r_badkey)
Verification failed due to an invalid key
.It Dv (-ns_r_badsig)
Verification failed due to an invalid signature
.It Dv (-ns_r_badtime)
Verification failed due to an invalid timestamp
.It Dv ns_r_badkey
Verification succeeded but the message had an error of BADKEY
.It Dv ns_r_badsig
Verification succeeded but the message had an error of BADSIG
.It Dv ns_r_badtime
Verification succeeded but the message had an error of BADTIME
.El
.Pp
.Sh SEE ALSO
.Xr resolver 3 .
.Sh AUTHORS
Brian Wellington, TISLabs at Network Associates
.\" .Sh BUGS