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ip/dhcpd: bring back interface address for arpenter()

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the arp table is per interface, so it is possible to have the same
netwrok on multiple physical interfaces, tho with different source
ip address. one example would be a ethernet and a wlan interface.
the mac addresses on these mediums can differ (arp proxying taking
place).

so provide our source address on the interface we received the
request on.

the previous change used the ifcaddr; which is correct; but due to a
oversight in the kernel, had to match the ip of the arp entry.
source address will always work.
This commit is contained in:
cinap_lenrek 2018-09-01 15:08:40 +02:00
parent 4e61bc282c
commit 5a2c3580fc
1 changed files with 13 additions and 12 deletions
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25
sys/src/cmd/ip/dhcpd/dhcpd.c
View file

@ -165,7 +165,7 @@ char *optname[256] =
void addropt(Req*, int, uchar*);
void addrsopt(Req*, int, uchar**, int);
void arpenter(uchar*, uchar*);
void arpenter(uchar*, uchar*, uchar*);
void bootp(Req*);
void byteopt(Req*, int, uchar);
void dhcp(Req*);
@ -746,7 +746,7 @@ sendoffer(Req *rp, uchar *ip, int offer)
} else {
ipmove(up->raddr, ip);
if(bp->htype == 1)
arpenter(up->raddr, bp->chaddr);
arpenter(up->raddr, bp->chaddr, up->laddr);
hnputs(up->rport, 68);
}
@ -805,7 +805,7 @@ sendack(Req *rp, uchar *ip, int offer, int sendlease)
} else {
ipmove(up->raddr, ip);
if(bp->htype == 1)
arpenter(up->raddr, bp->chaddr);
arpenter(up->raddr, bp->chaddr, up->laddr);
hnputs(up->rport, 68);
}
@ -993,7 +993,7 @@ bootp(Req *rp)
} else {
v4tov6(up->raddr, bp->yiaddr);
if(bp->htype == 1)
arpenter(up->raddr, bp->chaddr);
arpenter(up->raddr, bp->chaddr, up->laddr);
hnputs(up->rport, 68);
}
@ -1576,19 +1576,20 @@ hexopt(Req *rp, int t, char *str)
}
void
arpenter(uchar *ip, uchar *ether)
arpenter(uchar *ip, uchar *mac, uchar *src)
{
int f;
char buf[256];
int fd, n;
sprint(buf, "%s/arp", net);
f = open(buf, OWRITE);
if(f < 0){
syslog(debug, blog, "open %s: %r", buf);
snprint(buf, sizeof buf, "%s/arp", net);
if((fd = open(buf, OWRITE)) < 0){
warning("couldn't open %s: %r", buf);
return;
}
fprint(f, "add ether %I %E", ip, ether);
close(f);
n = snprint(buf, sizeof buf, "add ether %I %E %I\n", ip, mac, src);
if(write(fd, buf, n) != n)
warning("arpenter: %s: %r", buf);
close(fd);
}
char *dhcpmsgname[] =