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RDKB-64441: Redirect only XDNS clients to dnsmasq instead of all LAN clients - #462
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…clients Reason for change: All DNS traffic was redirected to dnsmasq when XDNS was enabled, so one flooding client could hit dnsmasq's 150-query forward limit and block DNS for all other clients. Test Procedure: Configure per-client and global XDNS, verify only intended clients are redirected. Risks: Low Priority: P1 Signed-off-by: rajkamal_cv@comcast.com
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🟡 Changes recommended
Malformed PUMA7 protocol options prevent NAT updates, and incorrect WAN resolver detection can preserve unintended all-client redirection.
2 open issues
What changed in this PR
This PR narrows firewall DNS redirection to XDNS-configured clients, aiming to prevent non-XDNS traffic from exhausting dnsmasq’s forwarding queue while preserving global XDNS behavior.
Changes:
- Parses
dnsoverrideentries to generate MAC-specific IPv4 and IPv6 redirects. - Adds default-resolver classification to determine when all-client redirection is needed.
- Centralizes redirect rule generation and reports redirect counts.
| File | Description |
|---|---|
| source/firewall/firewall.c | Adds XDNS configuration parsing and selective DNS redirect generation. |
Review effort: Balanced
Comment on lines
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| fprintf(nat_fp, "-A prerouting_fromlan -i %s ! -s 169.254.0.0/16 %sp udp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); | ||
| fprintf(nat_fp, "-A prerouting_fromlan -i %s ! -s 169.254.0.0/16 %sp tcp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); | ||
| #else | ||
| fprintf(nat_fp, "-A prerouting_fromlan -i %s %s-p udp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); | ||
| fprintf(nat_fp, "-A prerouting_fromlan -i %s %s-p tcp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); | ||
| #endif | ||
| } | ||
| else | ||
| { | ||
| #if defined (INTEL_PUMA7) | ||
| fprintf(nat_fp, "-A PREROUTING -i %s ! -s 2603:2000::/20 %sp udp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); | ||
| fprintf(nat_fp, "-A PREROUTING -i %s ! -s 2603:2000::/20 %sp tcp --dport 53 -j DNAT --to-destination %s\n",lan_ifname,mac_match,dns_dest); |
| if (iptype == 4) | ||
| { | ||
| int i; | ||
| const char *ns_keys[3] = {"dhcp_nameserver_1", "dhcp_nameserver_2", "dhcp_nameserver_3"}; |
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RDKB-64441: Redirect only XDNS clients to dnsmasq instead of all LAN clients
Reason for change: All DNS traffic was redirected to dnsmasq when XDNS was enabled, so one flooding client could hit dnsmasq's 150-query forward limit and block DNS for all other clients. Test Procedure: Configure per-client and global XDNS, verify only intended clients are redirected.
Risks: Low
Priority: P1
Signed-off-by: rajkamal_cv@comcast.com
Related PR - rdkcentral/xdns#33