Re: ntohs/ntohl and bitops

From: Ulrich Drepper
Date: Wed Jan 11 2006 - 03:34:43 EST


Arjan van de Ven wrote:
> why this __constant_htons and not just plain htons ??
> htons() gets auto-remapped to that anyway via the builtin "is this a
> constant" thing...... and to be honest htons() is more readable.

Indeed, why the need for the uglification?

Anyway, candidates for this kind of transformation:

net/ipx/af_ipx.c:1450: if (ntohs(addr->sipx_port) <
IPX_MIN_EPHEMERAL_SOCKET &&
net/atm/br2684.c:308: if (ntohs(eth->h_proto) >= 1536)
net/ipv6/netfilter/ip6t_LOG.c:114: if
(ntohs(fh->frag_off) & 0xFFF8)
net/ipv6/exthdrs_core.c:89: if (ntohs(*fp) & ~0x7)
net/ipv4/ipmr.c:1182: if (skb->len+encap > dst_mtu(&rt->u.dst) &&
(ntohs(iph->frag_off) & IP_DF)) {
net/ipv4/netfilter/ip_conntrack_helper_pptp.c:710: if
(ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
net/ipv4/netfilter/ipt_LOG.c:70: if (ntohs(ih->frag_off) & IP_CE)
net/ipv4/netfilter/ipt_LOG.c:72: if (ntohs(ih->frag_off) & IP_DF)
net/ipv4/netfilter/ipt_LOG.c:74: if (ntohs(ih->frag_off) & IP_MF)
net/ipv4/netfilter/ipt_LOG.c:78: if (ntohs(ih->frag_off) & IP_OFFSET)
net/ipv4/netfilter/ipt_LOG.c:108: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/ipv4/netfilter/ipt_LOG.c:180: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/ipv4/netfilter/ipt_LOG.c:221: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/ipv4/netfilter/ipt_LOG.c:286: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/ipv4/netfilter/ipt_LOG.c:311: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/bridge/netfilter/ebt_ip.c:55: if (ntohs(ih->frag_off)
& IP_OFFSET)
net/sunrpc/auth_gss/svcauth_gss.c:793: if (ntohl(svc_getu32(argv)) !=
RPC_GSS_VERSION)
net/sunrpc/auth_gss/svcauth_gss.c:823: if
(ntohl(svc_getu32(argv)) != RPC_AUTH_NULL)
net/sunrpc/auth_gss/svcauth_gss.c:825: if
(ntohl(svc_getu32(argv)) != 0)
net/bluetooth/bnep/core.c:343: if (ntohs(s->eh.h_proto) == 0x8100) {


(svcauth_gss.c:825 is a good one).



For consistency reasons, ntohs should be changed to htons here:

net/ipv6/netfilter/ip6t_eui64.c:43: if (eth_hdr(skb)->h_proto ==
ntohs(ETH_P_IPV6)) {


Around net/ipv4/ipconfig.c:376 you might want to store the transformed
ic_myaddr in a variable instead of repeating the ntohl call.

--
â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, CA â

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