Derive the DHCP subnet from the FOG address, not the interface (GH-1747) - #1753
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On an interface with more than one IPv4 address, the installer wrote a DHCP subnet that was not a network. The report shows a saved mask of 255.255.0.0 on a /24, a Kea subnet of "10.0.45.2/24", a pool starting at .12, and "arithmetic syntax error ... /8" during interface selection. Each helper took "the interface" and read a different address from it: - input.sh took every inet address, link-local 169.254.x.x included. Listed first, a link-local address became the primary. - getCidr() printed the SECOND global address's prefix (head -n2 | tail -n1), through an unanchored grep, so eth1 also read eth10. A global 169.254.x.x/16 next to a /24 gave 255.255.0.0. - configureDHCP and writeKeaSample passed every global address, unquoted, to mask2network, so a second address became the mask. 10.0.45.2 with 10.0.45.14 gave the network 10.0.45.2. - interface2broadcast() took the first brd, whichever address it belonged to. Now everything derives from $ipaddress, the address FOG advertises as next-server: - input.sh takes global addresses only, and never 169.254.0.0/16. - getCidr IFACE [ADDR] prints the prefix of ADDR, or of the first global address. It reads only that interface. - interface2broadcast IFACE [ADDR] prints the brd of ADDR. - configureDHCP and writeKeaSample use $ipaddress for the network. Also: - cidr2mask with no prefix returns nothing instead of printing the /8 arithmetic error. - mask2cidr: "224)" had `let` and `nbits+=3` on separate lines, a string append, so a /27 mask came out as 243. Its error message went to stdout, where every caller takes the value as the prefix; it now goes to stderr. - The ifconfig fallback in input.sh is removed. It stored mask2cidr's prefix length in $submask, and ifconfig is not installed before the package step. An empty mask is derived again in configureDHCP. - With -y, an interface with no usable address now exits. It used to repeat the same answer forever, and the link-local filter adds a way to reach that path. tests/installer-subnet-detection.test.sh replays address layouts through the real functions and the real input.sh lines, with a fake `ip` built from real `ip -o` output. On the old code it fails 33 of 47 checks and reproduces the report: "10.0.45.2/24", pool "10.0.45.12 - 10.0.45.254", the saved 255.255.0.0, and the /8 error. It passes all 47 after. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012JsEqysRdWb914YC94Shvo
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Problem
On an interface with more than one IPv4 address, the installer writes a DHCP subnet that is not a network. #1747 shows a saved mask of
255.255.0.0on a /24, a Kea subnet of"10.0.45.2/24", a pool starting at.12, andarithmetic syntax error ... /8during interface selection.Cause
Each helper reads "the interface" and takes a different address from it:
input.sh169.254.x.xincluded, so a link-local address listed first became the primarygetCidr()head -n2 | tail -n1), through an unanchored grep, soeth1also readeth10configureDHCP,writeKeaSamplemask2network, so a second address became the maskinterface2broadcast()brd, whichever address it belonged toA second address in the same /24 gives exactly the reported config.
10.0.45.2with10.0.45.14gives the network10.0.45.2. A global169.254.x.x/16next to the /24 gives the saved255.255.0.0. A link-local-only NIC gives the/8error.Fix
Everything derives from
$ipaddress, the address FOG advertises as next-server.input.shtakes global addresses only, and never169.254.0.0/16.getCidr IFACE [ADDR]andinterface2broadcast IFACE [ADDR]read the named address on that interface only.configureDHCPandwriteKeaSamplecompute the network from$ipaddress.cidr2maskwith no prefix returns nothing, instead of printing the arithmetic error.mask2cidr: the224)case was a string append, so a /27 mask came out as243. Its error message now goes to stderr instead of into the caller's value.ifconfigfallback ininput.shis removed. It stored a prefix length in$submask, andifconfigis not installed before the package step.Behavior change: with
-y, an interface with no usable address now exits. It used to repeat the same answer forever.Test
tests/installer-subnet-detection.test.shreplays address layouts through the real functions and the realinput.shlines. The fakeipprints realip -ooutput.The same fix for
working-1.6is in a separate PR.Refs #1747
🤖 Generated with Claude Code
https://claude.ai/code/session_012JsEqysRdWb914YC94Shvo