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|
#!/usr/bin/env bash
# Usage: mkhdr -l <len> -t <type> -f <flags> -sid <sid> > hdr.bin
# All fields are optional. 0 assumed when absent.
USAGE=\
"Usage: %s [-l <len> ] [-t <type>] [-f <flags>[,...]] [-i <sid>] [ -d <data> ]
[ -e <name> <value> ]* [ -r|-R raw ] [ -h | --help ] > hdr.bin
Numbers are decimal or 0xhex. Not set=0. If <data> is passed, it points
to a file that is read and chunked into frames of <len> bytes. -e
encodes a headers frame (by default) with all headers at once encoded
in literal. Use type 'p' for the preface. Use -r to pass raw data or
-R to pass raw hex codes (hex digit pairs, blanks ignored).
Supported symbolic types (case insensitive prefix match):
DATA (0x00) PUSH_PROMISE (0x05)
HEADERS (0x01) PING (0x06)
PRIORITY (0x02) GOAWAY (0x07)
RST_STREAM (0x03) WINDOW_UPDATE (0x08)
SETTINGS (0x04) CONTINUATION (0x09)
Supported symbolic flags (case insensitive prefix match):
ES (0x01) PAD (0x08)
EH (0x04) PRIO (0x20)
"
LEN=
TYPE=
FLAGS=
ID=
RAW=
HDR=( )
die() {
[ "$#" -eq 0 ] || echo "$*" >&2
exit 1
}
quit() {
[ "$#" -eq 0 ] || echo "$*"
exit 0
}
# print usage with $1 as the cmd name
usage() {
printf "$USAGE" "$1";
}
# Send frame made of $1 $2 $3 $4 to stdout.
# Usage: mkframe <len> <type> <flags> <id>
mkframe() {
local L="${1:-0}"
local T="${2:-0}"
local F="${3:-0}"
local I="${4:-0}"
local t f f2 f3
# get the first match in this order
for t in DATA:0x00 HEADERS:0x01 RST_STREAM:0x03 SETTINGS:0x04 PING:0x06 \
GOAWAY:0x07 WINDOW_UPDATE:0x08 CONTINUATION:0x09 PRIORITY:0x02 \
PUSH_PROMISE:0x05; do
if [ -z "${t##${T^^*}*}" ]; then
T="${t##*:}"
break
fi
done
if [ -n "${T##[0-9]*}" ]; then
echo "Unknown type '$T'" >&2
usage "${0##*}"
die
fi
# get the first match in this order, for each entry delimited by ','.
# E.g.: "-f ES,EH"
f2=${F^^*}; F=0
while [ -n "$f2" ]; do
f3="${f2%%,*}"
tmp=""
for f in ES:0x01 EH:0x04 PAD:0x08 PRIO:0x20; do
if [ -n "$f3" -a -z "${f##${f3}*}" ]; then
tmp="${f#*:}"
break
fi
done
if [ -n "$tmp" ]; then
F=$(( F | tmp ))
f2="${f2#$f3}"
f2="${f2#,}"
elif [ -z "${f3##[X0-9A-F]*}" ]; then
F=$(( F | f3 ))
f2="${f2#$f3}"
f2="${f2#,}"
else
echo "Unknown flag(s) '$f3'" >&2
usage "${0##*}"
die
fi
done
if [ -n "$f2" ]; then
F="${f2} | ${F}"
fi
L=$(( L )); T=$(( T )); F=$(( F )); I=$(( I ))
L0=$(( (L >> 16) & 255 )); L0=$(printf "%02x" $L0)
L1=$(( (L >> 8) & 255 )); L1=$(printf "%02x" $L1)
L2=$(( (L >> 0) & 255 )); L2=$(printf "%02x" $L2)
T0=$(( (T >> 0) & 255 )); T0=$(printf "%02x" $T0)
F0=$(( (F >> 0) & 255 )); F0=$(printf "%02x" $F0)
I0=$(( (I >> 24) & 127 )); I0=$(printf "%02x" $I0)
I1=$(( (I >> 16) & 255 )); I1=$(printf "%02x" $I1)
I2=$(( (I >> 8) & 255 )); I2=$(printf "%02x" $I2)
I3=$(( (I >> 0) & 255 )); I3=$(printf "%02x" $I3)
printf "\x$L0\x$L1\x$L2\x$T0\x$F0\x$I0\x$I1\x$I2\x$I3"
}
## main
if [ $# -le 1 ]; then
usage "${0##*}"
die
fi
while [ -n "$1" -a -z "${1##-*}" ]; do
case "$1" in
-l) LEN="$2" ; shift 2 ;;
-t) TYPE="$2" ; shift 2 ;;
-f) FLAGS="$2" ; shift 2 ;;
-i) ID="$2" ; shift 2 ;;
-d) DATA="$2" ; shift 2 ;;
-r) RAW="$2" ; shift 2 ;;
-R) RAW="$(printf $(echo -n "${2// /}" | sed -e 's/\([^ ][^ ]\)/\\\\x\1/g'))" ; shift 2 ;;
-e) TYPE=1; HDR[${#HDR[@]}]="$2=$3"; shift 3 ;;
-h|--help) usage "${0##*}"; quit;;
*) usage "${0##*}"; die ;;
esac
done
if [ $# -gt 0 ]; then
usage "${0##*}"
die
fi
# default values for LEN and ID
LEN=${LEN:-0};
if [ -n "${LEN##[0-9]*}" ]; then
echo "Unparsable length '$LEN'" >&2
usage "${0##*}"
die
fi
ID=${ID:-0};
if [ -n "${ID##[0-9]*}" ]; then
echo "Unparsable stream ID '$ID'" >&2
usage "${0##*}"
die
fi
if [ "$TYPE" = "p" ]; then
printf "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
elif [ -z "$DATA" ]; then
# If we're trying to emit literal headers, let's pre-build the raw data
# and measure their total length.
if [ ${#HDR[@]} -gt 0 ]; then
# limited to 127 bytes for name and value
for h in "${HDR[@]}"; do
n=${h%%=*}
v=${h#*=}
nl=${#n}
vl=${#v}
nl7=$(printf "%02x" $((nl & 127)))
vl7=$(printf "%02x" $((vl & 127)))
RAW="${RAW}\x40\x${nl7}${n}\x${vl7}${v}"
done
fi
# compute length if RAW set
if [ -n "$RAW" ]; then
LEN=$(printf "${RAW}" | wc -c)
fi
mkframe "$LEN" "$TYPE" "$FLAGS" "$ID"
# now emit the literal data of advertised length
if [ -n "$RAW" ]; then
printf "${RAW}"
fi
else
# read file $DATA in <LEN> chunks and send it in multiple frames
# advertising their respective lengths.
[ $LEN -gt 0 ] || LEN=16384
while read -rN "$LEN" payload || [ ${#payload} -gt 0 ]; do
mkframe "${#payload}" "$TYPE" "$FLAGS" "$ID"
echo -n "$payload"
done < "$DATA"
fi
exit 0
|
