Program size issue on 4.19 with IPv4-only and all advanced features

[pchaigno]

#17470 extends K8sVerifier to also test IPv4-only and IPv6-only. In the process, a new program size issue was found for 4.19 and IPv4-only.

Reproduction steps:

$ docker run --privileged -v `pwd`/:/cilium -v /sys/fs/bpf:/sys/fs/bpf --workdir /cilium -it quay.io/cilium/test-verifier:0f6647c542b71e89f310e437570b6d05dd9351bb make -C bpf bpf_lxc.o KERNEL=419 MAX_LXC_OPTIONS="-DSKIP_DEBUG=1 -DENABLE_IPV4=1 -DENABLE_HOST_SERVICES_TCP=1 -DENABLE_HOST_SERVICES_UDP=1 -DENABLE_HOST_REDIRECT=1 -DENABLE_ROUTING=1 -DNO_REDIRECT=1 -DPOLICY_VERDICT_NOTIFY=1 -DALLOW_ICMP_FRAG_NEEDED=1 -DENABLE_IDENTITY_MARK=1 -DMONITOR_AGGREGATION=3 -DCT_REPORT_FLAGS=0x0002 -DENABLE_HOST_FIREWALL=1 -DHAVE_LPM_TRIE_MAP_TYPE=1 -DHAVE_LRU_HASH_MAP_TYPE=1 -DENABLE_MASQUERADE=1 -DENABLE_SRC_RANGE_CHECK=1 -DENABLE_NODEPORT=1 -DENABLE_NODEPORT_ACCELERATION=1 -DENABLE_SESSION_AFFINITY=1 -DENABLE_DSR_ICMP_ERRORS=1 -DENABLE_DSR=1 -DENABLE_DSR_HYBRID=1 -DENABLE_IPV4_FRAGMENTS=1 -DENCAP_IFINDEX=1 -DTUNNEL_MODE=1 -DENABLE_EGRESS_GATEWAY=1"
$ docker run --privileged -v `pwd`/:/cilium -v /sys/fs/bpf:/sys/fs/bpf --workdir /cilium -it quay.io/cilium/test-verifier:0f6647c542b71e89f310e437570b6d05dd9351bb env XDP_PROGS="" CG_PROGS="" TC_PROGS="bpf_lxc" ./test/bpf/verifier-test.sh
[...]
Prog section 'from-container' rejected: Argument list too long (7)!
 - Type:         3
 - Attach Type:  0
 - Instructions: 4180 (84 over limit)
 - License:      GPL

A quick fix for this would be to compile the IPvX-specific tail calls even when only one of IPv4/IPv6 is enabled.