Align outgoing packets
Fixes #62
diff --git a/src/ncsi.c b/src/ncsi.c
index 738d83d..846da9a 100644
--- a/src/ncsi.c
+++ b/src/ncsi.c
@@ -268,10 +268,10 @@
{
const struct ncsi_pkt_hdr *nh =
(const struct ncsi_pkt_hdr *)(pkt + ETH_HLEN);
- uint8_t ncsi_reply[ETH_HLEN + NCSI_MAX_LEN];
- struct ethhdr *reh = (struct ethhdr *)ncsi_reply;
+ uint8_t ncsi_reply[2 + ETH_HLEN + NCSI_MAX_LEN];
+ struct ethhdr *reh = (struct ethhdr *)(ncsi_reply + 2);
struct ncsi_rsp_pkt_hdr *rnh =
- (struct ncsi_rsp_pkt_hdr *)(ncsi_reply + ETH_HLEN);
+ (struct ncsi_rsp_pkt_hdr *)(ncsi_reply + 2 + ETH_HLEN);
const struct ncsi_rsp_handler *handler = NULL;
int i;
int ncsi_rsp_len = sizeof(*nh);
@@ -322,5 +322,5 @@
*pchecksum = htonl(checksum);
ncsi_rsp_len += 4;
- slirp_send_packet_all(slirp, ncsi_reply, ETH_HLEN + ncsi_rsp_len);
+ slirp_send_packet_all(slirp, ncsi_reply + 2, ETH_HLEN + ncsi_rsp_len);
}
diff --git a/src/slirp.c b/src/slirp.c
index 3dff500..57d0768 100644
--- a/src/slirp.c
+++ b/src/slirp.c
@@ -1077,9 +1077,9 @@
{
const struct slirp_arphdr *ah =
(const struct slirp_arphdr *)(pkt + ETH_HLEN);
- uint8_t arp_reply[MAX(ETH_HLEN + sizeof(struct slirp_arphdr), 64)];
- struct ethhdr *reh = (struct ethhdr *)arp_reply;
- struct slirp_arphdr *rah = (struct slirp_arphdr *)(arp_reply + ETH_HLEN);
+ uint8_t arp_reply[MAX(2 + ETH_HLEN + sizeof(struct slirp_arphdr), 2 + 64)];
+ struct ethhdr *reh = (struct ethhdr *)(arp_reply + 2);
+ struct slirp_arphdr *rah = (struct slirp_arphdr *)(arp_reply + 2 + ETH_HLEN);
int ar_op;
struct gfwd_list *ex_ptr;
@@ -1132,7 +1132,7 @@
rah->ar_sip = ah->ar_tip;
memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
rah->ar_tip = ah->ar_sip;
- slirp_send_packet_all(slirp, arp_reply, sizeof(arp_reply));
+ slirp_send_packet_all(slirp, arp_reply + 2, sizeof(arp_reply) - 2);
}
break;
case ARPOP_REPLY:
@@ -1161,8 +1161,8 @@
m = m_get(slirp);
if (!m)
return;
- /* Note: we add 2 to align the IP header on 4 bytes,
- * and add the margin for the tcpiphdr overhead */
+ /* Note: we add 2 to align the IP header on 8 bytes despite the ethernet
+ * header, and add the margin for the tcpiphdr overhead */
if (M_FREEROOM(m) < pkt_len + TCPIPHDR_DELTA + 2) {
m_inc(m, pkt_len + TCPIPHDR_DELTA + 2);
}
@@ -1198,9 +1198,9 @@
const struct ip *iph = (const struct ip *)ifm->m_data;
if (!arp_table_search(slirp, iph->ip_dst.s_addr, ethaddr)) {
- uint8_t arp_req[ETH_HLEN + sizeof(struct slirp_arphdr)];
- struct ethhdr *reh = (struct ethhdr *)arp_req;
- struct slirp_arphdr *rah = (struct slirp_arphdr *)(arp_req + ETH_HLEN);
+ uint8_t arp_req[2 + ETH_HLEN + sizeof(struct slirp_arphdr)];
+ struct ethhdr *reh = (struct ethhdr *)(arp_req + 2);
+ struct slirp_arphdr *rah = (struct slirp_arphdr *)(arp_req + 2 + ETH_HLEN);
if (!ifm->resolution_requested) {
/* If the client addr is not known, send an ARP request */
@@ -1227,7 +1227,7 @@
/* target IP */
rah->ar_tip = iph->ip_dst.s_addr;
slirp->client_ipaddr = iph->ip_dst;
- slirp_send_packet_all(slirp, arp_req, sizeof(arp_req));
+ slirp_send_packet_all(slirp, arp_req + 2, sizeof(arp_req) - 2);
ifm->resolution_requested = true;
/* Expire request and drop outgoing packet after 1 second */
@@ -1277,13 +1277,13 @@
int if_encap(Slirp *slirp, struct mbuf *ifm)
{
uint8_t buf[IF_MTU_MAX + 100];
- struct ethhdr *eh = (struct ethhdr *)buf;
+ struct ethhdr *eh = (struct ethhdr *)(buf + 2);
uint8_t ethaddr[ETH_ALEN];
const struct ip *iph = (const struct ip *)ifm->m_data;
int ret;
char ethaddr_str[ETH_ADDRSTRLEN];
- if (ifm->m_len + ETH_HLEN > sizeof(buf)) {
+ if (ifm->m_len + ETH_HLEN > sizeof(buf) - 2) {
return 1;
}
@@ -1311,8 +1311,8 @@
sizeof(ethaddr_str)));
DEBUG_ARG("dst = %s", slirp_ether_ntoa(eh->h_dest, ethaddr_str,
sizeof(ethaddr_str)));
- memcpy(buf + sizeof(struct ethhdr), ifm->m_data, ifm->m_len);
- slirp_send_packet_all(slirp, buf, ifm->m_len + ETH_HLEN);
+ memcpy(buf + 2 + sizeof(struct ethhdr), ifm->m_data, ifm->m_len);
+ slirp_send_packet_all(slirp, buf + 2, ifm->m_len + ETH_HLEN);
return 1;
}
