int
ipv4_output(struct reply *reply, struct request *req)
{
unsigned short len;
u_int32_t sum;
if (reply->off <= 0)
fatalx("bad reply offset");
len = sizeof reply->pkt.bootp + reply->off;
reply->pkt.l3.ip_v = 4;
reply->pkt.l3.ip_hl = 5;
reply->pkt.l3.ip_ttl = 16;
reply->pkt.l3.ip_len = htons(len +
sizeof reply->pkt.l3 + sizeof reply->pkt.l4);
reply->pkt.l3.ip_tos = IPTOS_LOWDELAY;
reply->pkt.l3.ip_p = IPPROTO_UDP;
reply->pkt.l3.ip_src = ipv4_addr(req->rcvd_on);
reply->pkt.l3.ip_dst = destination(reply, req, &reply->pkt.l4.uh_dport);
/* Fill in IPv4 checksum. */
sum = checksum(&reply->pkt.l3, sizeof reply->pkt.l3, 0);
reply->pkt.l3.ip_sum = wrapsum(sum);
/* Fill in UDP checksum, now that we have the IPv4 header. */
sum = ntohs(reply->pkt.l4.uh_ulen) + IPPROTO_UDP;
sum = checksum(&reply->pkt.l3.ip_src, 2 * sizeof(struct in_addr), sum);
sum = checksum(&reply->pkt.bootp, len, sum);
sum = checksum(&reply->pkt.l4, sizeof reply->pkt.l4, sum);
reply->pkt.l4.uh_sum = wrapsum(sum);
return 20;
}
bool netblock_match(const struct sockaddr_storage *ss1,
const struct sockaddr_storage *ss2,
unsigned prefix)
{
if (ss1 == NULL || ss2 == NULL) {
return false;
}
if (ss1->ss_family != ss2->ss_family) {
return false;
}
const uint8_t *addr1, *addr2;
switch (ss1->ss_family) {
case AF_INET:
addr1 = ipv4_addr(ss1);
addr2 = ipv4_addr(ss2);
prefix = prefix > IPV4_PREFIXLEN ? IPV4_PREFIXLEN : prefix;
break;
case AF_INET6:
addr1 = ipv6_addr(ss1);
addr2 = ipv6_addr(ss2);
prefix = prefix > IPV6_PREFIXLEN ? IPV6_PREFIXLEN : prefix;
break;
default:
return false;
}
/* Compare full bytes address block. */
uint8_t full_bytes = prefix / 8;
for (int i = 0; i < full_bytes; i++) {
if (addr1[i] != addr2[i]) {
return false;
}
}
/* Compare last partial byte address block. */
uint8_t rest_bits = prefix % 8;
if (rest_bits > 0) {
uint8_t rest1 = addr1[full_bytes] >> (8 - rest_bits);
uint8_t rest2 = addr2[full_bytes] >> (8 - rest_bits);
if (rest1 != rest2) {
return false;
}
}
int port(struct sockaddr_storage *addr)
{
if (AF_INET == addr->ss_family)
{
return ntohs(ipv4_addr(addr)->sin_port);
}
else if (AF_INET6 == addr->ss_family)
{
return ntohs(ipv6_addr(addr)->sin6_port);
}
return 0;
}
const char *inet_ntop(struct sockaddr_storage *addr)
{
if (AF_INET == addr->ss_family)
{
return ::inet_ntop(AF_INET, &(ipv4_addr(addr)->sin_addr), m_buffer, sizeof(m_buffer));
}
else if (AF_INET6 == addr->ss_family)
{
return ::inet_ntop(AF_INET6, &(ipv6_addr(addr)->sin6_addr), m_buffer, sizeof(m_buffer));
}
return NULL;
}
