ref: 75c92428225428c8fde2d015f010e608a0b12f1d
dir: /os/ip/ipaux.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "ip.h"
#include "ipv6.h"
/*
* well known IP addresses
*/
uchar IPv4bcast[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff
};
uchar IPv4allsys[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0xff, 0xff,
0xe0, 0, 0, 0x01
};
uchar IPv4allrouter[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0xff, 0xff,
0xe0, 0, 0, 0x02
};
uchar IPallbits[IPaddrlen] = {
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff
};
uchar IPnoaddr[IPaddrlen];
/*
* prefix of all v4 addresses
*/
uchar v4prefix[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0xff, 0xff,
0, 0, 0, 0
};
char *v6hdrtypes[Maxhdrtype] =
{
[HBH] "HopbyHop",
[ICMP] "ICMP",
[IGMP] "IGMP",
[GGP] "GGP",
[IPINIP] "IP",
[ST] "ST",
[TCP] "TCP",
[UDP] "UDP",
[ISO_TP4] "ISO_TP4",
[RH] "Routinghdr",
[FH] "Fraghdr",
[IDRP] "IDRP",
[RSVP] "RSVP",
[AH] "Authhdr",
[ESP] "ESP",
[ICMPv6] "ICMPv6",
[NNH] "Nonexthdr",
[ISO_IP] "ISO_IP",
[IGRP] "IGRP",
[OSPF] "OSPF",
};
/*
* well known IPv6 addresses
*/
uchar v6Unspecified[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
uchar v6loopback[IPaddrlen] = {
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x01
};
uchar v6linklocal[IPaddrlen] = {
0xfe, 0x80, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
uchar v6linklocalmask[IPaddrlen] = {
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 0, 0, 0,
0, 0, 0, 0
};
int v6llpreflen = 8; // link-local prefix length
uchar v6sitelocal[IPaddrlen] = {
0xfe, 0xc0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
uchar v6sitelocalmask[IPaddrlen] = {
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 0, 0, 0,
0, 0, 0, 0
};
int v6slpreflen = 6; // site-local prefix length
uchar v6glunicast[IPaddrlen] = {
0x08, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
uchar v6multicast[IPaddrlen] = {
0xff, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
uchar v6multicastmask[IPaddrlen] = {
0xff, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
int v6mcpreflen = 1; // multicast prefix length
uchar v6allnodesN[IPaddrlen] = {
0xff, 0x01, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x01
};
uchar v6allnodesNmask[IPaddrlen] = {
0xff, 0xff, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
int v6aNpreflen = 2; // all nodes (N) prefix
uchar v6allnodesL[IPaddrlen] = {
0xff, 0x02, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x01
};
uchar v6allnodesLmask[IPaddrlen] = {
0xff, 0xff, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0
};
int v6aLpreflen = 2; // all nodes (L) prefix
uchar v6allroutersN[IPaddrlen] = {
0xff, 0x01, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x02
};
uchar v6allroutersL[IPaddrlen] = {
0xff, 0x02, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x02
};
uchar v6allroutersS[IPaddrlen] = {
0xff, 0x05, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x02
};
uchar v6solicitednode[IPaddrlen] = {
0xff, 0x02, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0x01,
0xff, 0, 0, 0
};
uchar v6solicitednodemask[IPaddrlen] = {
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0xff, 0x0, 0x0, 0x0
};
int v6snpreflen = 13;
ushort
ptclcsum(Block *bp, int offset, int len)
{
uchar *addr;
ulong losum, hisum;
ushort csum;
int odd, blocklen, x;
/* Correct to front of data area */
while(bp != nil && offset && offset >= BLEN(bp)) {
offset -= BLEN(bp);
bp = bp->next;
}
if(bp == nil)
return 0;
addr = bp->rp + offset;
blocklen = BLEN(bp) - offset;
if(bp->next == nil) {
if(blocklen < len)
len = blocklen;
return ~ptclbsum(addr, len) & 0xffff;
}
losum = 0;
hisum = 0;
odd = 0;
while(len) {
x = blocklen;
if(len < x)
x = len;
csum = ptclbsum(addr, x);
if(odd)
hisum += csum;
else
losum += csum;
odd = (odd+x) & 1;
len -= x;
bp = bp->next;
if(bp == nil)
break;
blocklen = BLEN(bp);
addr = bp->rp;
}
losum += hisum>>8;
losum += (hisum&0xff)<<8;
while((csum = losum>>16) != 0)
losum = csum + (losum & 0xffff);
return ~losum & 0xffff;
}
enum
{
Isprefix= 16,
};
static uchar prefixvals[256] =
{
[0x00] 0 | Isprefix,
[0x80] 1 | Isprefix,
[0xC0] 2 | Isprefix,
[0xE0] 3 | Isprefix,
[0xF0] 4 | Isprefix,
[0xF8] 5 | Isprefix,
[0xFC] 6 | Isprefix,
[0xFE] 7 | Isprefix,
[0xFF] 8 | Isprefix,
};
int
eipfmt(Fmt *f)
{
char buf[5*8];
static char *efmt = "%.2lux%.2lux%.2lux%.2lux%.2lux%.2lux";
static char *ifmt = "%d.%d.%d.%d";
uchar *p, ip[16];
ulong *lp;
ushort s;
int i, j, n, eln, eli;
switch(f->r) {
case 'E': /* Ethernet address */
p = va_arg(f->args, uchar*);
return fmtprint(f, efmt, p[0], p[1], p[2], p[3], p[4], p[5]);
case 'I': /* Ip address */
p = va_arg(f->args, uchar*);
common:
if(memcmp(p, v4prefix, 12) == 0)
return fmtprint(f, ifmt, p[12], p[13], p[14], p[15]);
/* find longest elision */
eln = eli = -1;
for(i = 0; i < 16; i += 2){
for(j = i; j < 16; j += 2)
if(p[j] != 0 || p[j+1] != 0)
break;
if(j > i && j - i > eln){
eli = i;
eln = j - i;
}
}
/* print with possible elision */
n = 0;
for(i = 0; i < 16; i += 2){
if(i == eli){
n += sprint(buf+n, "::");
i += eln;
if(i >= 16)
break;
} else if(i != 0)
n += sprint(buf+n, ":");
s = (p[i]<<8) + p[i+1];
n += sprint(buf+n, "%ux", s);
}
return fmtstrcpy(f, buf);
case 'i': /* v6 address as 4 longs */
lp = va_arg(f->args, ulong*);
for(i = 0; i < 4; i++)
hnputl(ip+4*i, *lp++);
p = ip;
goto common;
case 'V': /* v4 ip address */
p = va_arg(f->args, uchar*);
return fmtprint(f, ifmt, p[0], p[1], p[2], p[3]);
case 'M': /* ip mask */
p = va_arg(f->args, uchar*);
/* look for a prefix mask */
for(i = 0; i < 16; i++)
if(p[i] != 0xff)
break;
if(i < 16){
if((prefixvals[p[i]] & Isprefix) == 0)
goto common;
for(j = i+1; j < 16; j++)
if(p[j] != 0)
goto common;
n = 8*i + (prefixvals[p[i]] & ~Isprefix);
} else
n = 8*16;
/* got one, use /xx format */
return fmtprint(f, "/%d", n);
}
return fmtstrcpy(f, "(eipfmt)");
}
#define CLASS(p) ((*(uchar*)(p))>>6)
extern char*
v4parseip(uchar *to, char *from)
{
int i;
char *p;
p = from;
for(i = 0; i < 4 && *p; i++){
to[i] = strtoul(p, &p, 0);
if(*p == '.')
p++;
}
switch(CLASS(to)){
case 0: /* class A - 1 uchar net */
case 1:
if(i == 3){
to[3] = to[2];
to[2] = to[1];
to[1] = 0;
} else if(i == 2){
to[3] = to[1];
to[1] = 0;
}
break;
case 2: /* class B - 2 uchar net */
if(i == 3){
to[3] = to[2];
to[2] = 0;
}
break;
}
return p;
}
int
isv4(uchar *ip)
{
return memcmp(ip, v4prefix, IPv4off) == 0;
}
/*
* the following routines are unrolled with no memset's to speed
* up the usual case
*/
void
v4tov6(uchar *v6, uchar *v4)
{
v6[0] = 0;
v6[1] = 0;
v6[2] = 0;
v6[3] = 0;
v6[4] = 0;
v6[5] = 0;
v6[6] = 0;
v6[7] = 0;
v6[8] = 0;
v6[9] = 0;
v6[10] = 0xff;
v6[11] = 0xff;
v6[12] = v4[0];
v6[13] = v4[1];
v6[14] = v4[2];
v6[15] = v4[3];
}
int
v6tov4(uchar *v4, uchar *v6)
{
if(v6[0] == 0
&& v6[1] == 0
&& v6[2] == 0
&& v6[3] == 0
&& v6[4] == 0
&& v6[5] == 0
&& v6[6] == 0
&& v6[7] == 0
&& v6[8] == 0
&& v6[9] == 0
&& v6[10] == 0xff
&& v6[11] == 0xff)
{
v4[0] = v6[12];
v4[1] = v6[13];
v4[2] = v6[14];
v4[3] = v6[15];
return 0;
} else {
memset(v4, 0, 4);
return -1;
}
}
ulong
parseip(uchar *to, char *from)
{
int i, elipsis = 0, v4 = 1;
ulong x;
char *p, *op;
memset(to, 0, IPaddrlen);
p = from;
for(i = 0; i < 16 && *p; i+=2){
op = p;
x = strtoul(p, &p, 16);
if(*p == '.' || (*p == 0 && i == 0)){
p = v4parseip(to+i, op);
i += 4;
break;
} else {
to[i] = x>>8;
to[i+1] = x;
}
if(*p == ':'){
v4 = 0;
if(*++p == ':'){
elipsis = i+2;
p++;
}
}
}
if(i < 16){
memmove(&to[elipsis+16-i], &to[elipsis], i-elipsis);
memset(&to[elipsis], 0, 16-i);
}
if(v4){
to[10] = to[11] = 0xff;
return nhgetl(to+12);
} else
return 6;
}
/*
* hack to allow ip v4 masks to be entered in the old
* style
*/
ulong
parseipmask(uchar *to, char *from)
{
ulong x;
int i;
uchar *p;
if(*from == '/'){
/* as a number of prefix bits */
i = atoi(from+1);
if(i < 0)
i = 0;
if(i > 128)
i = 128;
memset(to, 0, IPaddrlen);
for(p = to; i >= 8; i -= 8)
*p++ = 0xff;
if(i > 0)
*p = ~((1<<(8-i))-1);
x = nhgetl(to+IPv4off);
} else {
/* as a straight bit mask */
x = parseip(to, from);
if(memcmp(to, v4prefix, IPv4off) == 0)
memset(to, 0xff, IPv4off);
}
return x;
}
void
maskip(uchar *from, uchar *mask, uchar *to)
{
int i;
for(i = 0; i < IPaddrlen; i++)
to[i] = from[i] & mask[i];
}
uchar classmask[4][16] = {
0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0x00,0x00,0x00,
0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0x00,0x00,0x00,
0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0x00,0x00,
0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0x00,
};
uchar*
defmask(uchar *ip)
{
if(isv4(ip))
return classmask[ip[IPv4off]>>6];
else {
if(ipcmp(ip, v6loopback) == 0)
return IPallbits;
else if(memcmp(ip, v6linklocal, v6llpreflen) == 0)
return v6linklocalmask;
else if(memcmp(ip, v6sitelocal, v6slpreflen) == 0)
return v6sitelocalmask;
else if(memcmp(ip, v6solicitednode, v6snpreflen) == 0)
return v6solicitednodemask;
else if(memcmp(ip, v6multicast, v6mcpreflen) == 0)
return v6multicastmask;
return IPallbits;
}
}
void
ipv62smcast(uchar *smcast, uchar *a)
{
assert(IPaddrlen == 16);
memmove(smcast, v6solicitednode, IPaddrlen);
smcast[13] = a[13];
smcast[14] = a[14];
smcast[15] = a[15];
}
/*
* parse a hex mac address
*/
int
parsemac(uchar *to, char *from, int len)
{
char nip[4];
char *p;
int i;
p = from;
memset(to, 0, len);
for(i = 0; i < len; i++){
if(p[0] == '\0' || p[1] == '\0')
break;
nip[0] = p[0];
nip[1] = p[1];
nip[2] = '\0';
p += 2;
to[i] = strtoul(nip, 0, 16);
if(*p == ':')
p++;
}
return i;
}
/*
* hashing tcp, udp, ... connections
*/
ulong
iphash(uchar *sa, ushort sp, uchar *da, ushort dp)
{
return ((sa[IPaddrlen-1]<<24) ^ (sp << 16) ^ (da[IPaddrlen-1]<<8) ^ dp ) % Nhash;
}
void
iphtadd(Ipht *ht, Conv *c)
{
ulong hv;
Iphash *h;
hv = iphash(c->raddr, c->rport, c->laddr, c->lport);
h = smalloc(sizeof(*h));
if(ipcmp(c->raddr, IPnoaddr) != 0)
h->match = IPmatchexact;
else {
if(ipcmp(c->laddr, IPnoaddr) != 0){
if(c->lport == 0)
h->match = IPmatchaddr;
else
h->match = IPmatchpa;
} else {
if(c->lport == 0)
h->match = IPmatchany;
else
h->match = IPmatchport;
}
}
h->c = c;
lock(ht);
h->next = ht->tab[hv];
ht->tab[hv] = h;
unlock(ht);
}
void
iphtrem(Ipht *ht, Conv *c)
{
ulong hv;
Iphash **l, *h;
hv = iphash(c->raddr, c->rport, c->laddr, c->lport);
lock(ht);
for(l = &ht->tab[hv]; (*l) != nil; l = &(*l)->next)
if((*l)->c == c){
h = *l;
(*l) = h->next;
free(h);
break;
}
unlock(ht);
}
/* look for a matching conversation with the following precedence
* connected && raddr,rport,laddr,lport
* announced && laddr,lport
* announced && *,lport
* announced && laddr,*
* announced && *,*
*/
Conv*
iphtlook(Ipht *ht, uchar *sa, ushort sp, uchar *da, ushort dp)
{
ulong hv;
Iphash *h;
Conv *c;
/* exact 4 pair match (connection) */
hv = iphash(sa, sp, da, dp);
lock(ht);
for(h = ht->tab[hv]; h != nil; h = h->next){
if(h->match != IPmatchexact)
continue;
c = h->c;
if(sp == c->rport && dp == c->lport
&& ipcmp(sa, c->raddr) == 0 && ipcmp(da, c->laddr) == 0){
unlock(ht);
return c;
}
}
/* match local address and port */
hv = iphash(IPnoaddr, 0, da, dp);
for(h = ht->tab[hv]; h != nil; h = h->next){
if(h->match != IPmatchpa)
continue;
c = h->c;
if(dp == c->lport && ipcmp(da, c->laddr) == 0){
unlock(ht);
return c;
}
}
/* match just port */
hv = iphash(IPnoaddr, 0, IPnoaddr, dp);
for(h = ht->tab[hv]; h != nil; h = h->next){
if(h->match != IPmatchport)
continue;
c = h->c;
if(dp == c->lport){
unlock(ht);
return c;
}
}
/* match local address */
hv = iphash(IPnoaddr, 0, da, 0);
for(h = ht->tab[hv]; h != nil; h = h->next){
if(h->match != IPmatchaddr)
continue;
c = h->c;
if(ipcmp(da, c->laddr) == 0){
unlock(ht);
return c;
}
}
/* look for something that matches anything */
hv = iphash(IPnoaddr, 0, IPnoaddr, 0);
for(h = ht->tab[hv]; h != nil; h = h->next){
if(h->match != IPmatchany)
continue;
c = h->c;
unlock(ht);
return c;
}
unlock(ht);
return nil;
}