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110 lines
2.1 KiB
110 lines
2.1 KiB
#!/bin/bash |
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get_addr () { |
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local if_name=$1 |
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local uri_template=$2 |
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ip addr show dev $if_name | awk -v uri=$uri_template '/\s*inet\s/ { \ |
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ip=gensub(/(.+)\/.+/, "\\1", "g", $2); \ |
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print gensub(/^(.+:\/\/).+(:.+)$/, "\\1" ip "\\2", "g", uri); \ |
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exit}' |
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} |
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# converts IPv4 as "A.B.C.D" to integer |
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ip4_to_int() { |
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IFS=. read -r i j k l <<EOF |
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$1 |
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EOF |
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echo $(( (i << 24) + (j << 16) + (k << 8) + l )) |
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} |
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# converts interger to IPv4 as "A.B.C.D" |
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int_to_ip4() { |
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echo "$(( ($1 >> 24) % 256 )).$(( ($1 >> 16) % 256 )).$(( ($1 >> 8) % 256 )).$(( $1 % 256 ))" |
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} |
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# returns the ip part of an CIDR |
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cidr_ip() { |
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IFS=/ read -r ip _ <<EOF |
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$1 |
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EOF |
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echo $ip |
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} |
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# returns the prefix part of an CIDR |
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cidr_prefix() { |
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IFS=/ read -r _ prefix <<EOF |
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$1 |
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EOF |
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echo $prefix |
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} |
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# returns net mask in numberic from prefix size |
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netmask_of_prefix() { |
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echo $((4294967295 ^ (1 << (32 - $1)) - 1)) |
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} |
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# returns default gateway address (network address + 1) from CIDR |
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cidr_default_gw() { |
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ip=$(ip4_to_int $(cidr_ip $1)) |
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prefix=$(cidr_prefix $1) |
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netmask=$(netmask_of_prefix $prefix) |
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gw=$((ip & netmask + 1)) |
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int_to_ip4 $gw |
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} |
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# returns default gateway address (broadcast address - 1) from CIDR |
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cidr_default_gw_2() { |
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ip=$(ip4_to_int $(cidr_ip $1)) |
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prefix=$(cidr_prefix $1) |
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netmask=$(netmask_of_prefix $prefix) |
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broadcast=$(((4294967295 - netmask) | ip)) |
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int_to_ip4 $((broadcast - 1)) |
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} |
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ip4_to_int 192.168.0.1 |
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# => 3232235521 |
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int_to_ip4 3232235521 |
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# => 192.168.0.1 |
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# network address |
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ip=$(ip4_to_int 172.16.10.20) |
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netmask=$(ip4_to_int 255.255.252.0) |
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int_to_ip4 $((ip & netmask)) |
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# => 172.16.8.0 |
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# broadcast address |
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ip=$(ip4_to_int 172.16.10.20) |
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netmask=$(ip4_to_int 255.255.252.0) |
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int_to_ip4 $(((ip & netmask) + 1)) |
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# => 172.16.8.1 |
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cidr_ip "172.16.0.10/22" |
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# => 172.16.0.10 |
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cidr_prefix "172.16.0.10/22" |
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# => 22 |
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netmask_of_prefix 8 |
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# => 4278190080 |
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cidr_default_gw 192.168.10.1/24 |
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# => 192.168.10.1 |
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cidr_default_gw 192.168.10.1/16 |
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# => 192.168.0.1 |
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cidr_default_gw 172.17.18.19/20 |
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# => 172.17.16.1 |
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cidr_default_gw_2 192.168.10.1/24 |
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# => 192.168.10.254 |
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cidr_default_gw_2 192.168.10.1/16 |
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# => 192.168.255.254 |
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cidr_default_gw_2 172.17.18.19/20 |
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# => 172.17.31.254 |