We have different versions of this function for IPv4 and IPv6, but the
caller already requires some IP version specific code to get the right
header pointers. Instead, have a common function that fills either an
IPv4 or an IPv6 header based on which header pointer it is passed. This
allows us to remove a small amount of code duplication and make a few
slightly ugly conditionals.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tcp.c | 108 ++++++++++++++++++++++---------------------------
tcp_buf.c | 19 ++++-----
tcp_internal.h | 13 +++---
tcp_vu.c | 32 ++++++---------
4 files changed, 75 insertions(+), 97 deletions(-)
diff --git a/tcp.c b/tcp.c
index 482e460..1872ccb 100644
--- a/tcp.c
+++ b/tcp.c
@@ -877,94 +877,82 @@ static void tcp_fill_header(struct tcphdr *th,
}
/**
- * tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
+ * tcp_fill_headers() - Fill 802.3, IP, TCP headers
* @conn: Connection pointer
* @taph: tap backend specific header
- * @iph: Pointer to IPv4 header
+ * @ip4h: Pointer to IPv4 header, or NULL
+ * @ip6h: Pointer to IPv6 header, or NULL
* @th: Pointer to TCP header
* @payload: TCP payload
- * @check: Checksum, if already known
+ * @ip4_check: IPv4 checksum, if already known
* @seq: Sequence number for this segment
* @no_tcp_csum: Do not set TCP checksum
*/
-void tcp_fill_headers4(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph, struct iphdr *iph,
- struct tcphdr *th, struct iov_tail *payload,
- const uint16_t *check, uint32_t seq, bool no_tcp_csum)
+void tcp_fill_headers(const struct tcp_tap_conn *conn,
+ struct tap_hdr *taph,
+ struct iphdr *ip4h, struct ipv6hdr *ip6h,
+ struct tcphdr *th, struct iov_tail *payload,
+ const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum)
{
const struct flowside *tapside = TAPFLOW(conn);
- const struct in_addr *src4 = inany_v4(&tapside->oaddr);
- const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
size_t l4len = iov_tail_size(payload) + sizeof(*th);
- size_t l3len = l4len + sizeof(*iph);
+ size_t l3len = l4len;
+ uint32_t psum = 0;
- ASSERT(src4 && dst4);
+ if (ip4h) {
+ const struct in_addr *src4 = inany_v4(&tapside->oaddr);
+ const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
- iph->tot_len = htons(l3len);
- iph->saddr = src4->s_addr;
- iph->daddr = dst4->s_addr;
+ ASSERT(src4 && dst4);
- iph->check = check ? *check :
- csum_ip4_header(l3len, IPPROTO_TCP, *src4, *dst4);
+ l3len += + sizeof(*ip4h);
- tcp_fill_header(th, conn, seq);
+ ip4h->tot_len = htons(l3len);
+ ip4h->saddr = src4->s_addr;
+ ip4h->daddr = dst4->s_addr;
- if (no_tcp_csum) {
- th->check = 0;
- } else {
- uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
- *src4, *dst4);
+ if (ip4_check)
+ ip4h->check = *ip4_check;
+ else
+ ip4h->check = csum_ip4_header(l3len, IPPROTO_TCP,
+ *src4, *dst4);
- tcp_update_csum(psum, th, payload);
+ if (!no_tcp_csum) {
+ psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
+ *src4, *dst4);
+ }
}
- tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
-}
+ if (ip6h) {
+ l3len += sizeof(*ip6h);
-/**
- * tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
- * @conn: Connection pointer
- * @taph: tap backend specific header
- * @ip6h: Pointer to IPv6 header
- * @th: Pointer to TCP header
- * @payload: TCP payload
- * @check: Checksum, if already known
- * @seq: Sequence number for this segment
- * @no_tcp_csum: Do not set TCP checksum
- */
-void tcp_fill_headers6(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph, struct ipv6hdr *ip6h,
- struct tcphdr *th, struct iov_tail *payload,
- uint32_t seq, bool no_tcp_csum)
-{
- size_t l4len = iov_tail_size(payload) + sizeof(*th);
- const struct flowside *tapside = TAPFLOW(conn);
+ ip6h->payload_len = htons(l4len);
+ ip6h->saddr = tapside->oaddr.a6;
+ ip6h->daddr = tapside->eaddr.a6;
- ip6h->payload_len = htons(l4len);
- ip6h->saddr = tapside->oaddr.a6;
- ip6h->daddr = tapside->eaddr.a6;
+ ip6h->hop_limit = 255;
+ ip6h->version = 6;
+ ip6h->nexthdr = IPPROTO_TCP;
- ip6h->hop_limit = 255;
- ip6h->version = 6;
- ip6h->nexthdr = IPPROTO_TCP;
+ ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
+ ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
+ ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
- ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
- ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
- ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
+ if (!no_tcp_csum) {
+ psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
+ &ip6h->saddr,
+ &ip6h->daddr);
+ }
+ }
tcp_fill_header(th, conn, seq);
- if (no_tcp_csum) {
+ if (no_tcp_csum)
th->check = 0;
- } else {
- uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
- &ip6h->saddr,
- &ip6h->daddr);
-
+ else
tcp_update_csum(psum, th, payload);
- }
- tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
+ tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
}
/**
diff --git a/tcp_buf.c b/tcp_buf.c
index 830c23d..a975a55 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -161,18 +161,19 @@ static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn
*conn,
{
struct iov_tail tail = IOV_TAIL(&iov[TCP_IOV_PAYLOAD], 1, 0);
struct tcphdr *th = IOV_REMOVE_HEADER(&tail, struct tcphdr);
+ struct tap_hdr *taph = iov[TCP_IOV_TAP].iov_base;
const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *a4 = inany_v4(&tapside->oaddr);
+ struct ipv6hdr *ip6h = NULL;
+ struct iphdr *ip4h = NULL;
- if (a4) {
- tcp_fill_headers4(conn, iov[TCP_IOV_TAP].iov_base,
- iov[TCP_IOV_IP].iov_base, th,
- &tail, check, seq, no_tcp_csum);
- } else {
- tcp_fill_headers6(conn, iov[TCP_IOV_TAP].iov_base,
- iov[TCP_IOV_IP].iov_base, th,
- &tail, seq, no_tcp_csum);
- }
+ if (a4)
+ ip4h = iov[TCP_IOV_IP].iov_base;
+ else
+ ip6h = iov[TCP_IOV_IP].iov_base;
+
+ tcp_fill_headers(conn, taph, ip4h, ip6h, th, &tail,
+ check, seq, no_tcp_csum);
}
/**
diff --git a/tcp_internal.h b/tcp_internal.h
index cff06e0..94e5780 100644
--- a/tcp_internal.h
+++ b/tcp_internal.h
@@ -164,14 +164,11 @@ struct tcp_info_linux;
void tcp_update_csum(uint32_t psum, struct tcphdr *th,
struct iov_tail *payload);
-void tcp_fill_headers4(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph, struct iphdr *iph,
- struct tcphdr *th, struct iov_tail *payload,
- const uint16_t *check, uint32_t seq, bool no_tcp_csum);
-void tcp_fill_headers6(const struct tcp_tap_conn *conn,
- struct tap_hdr *taph, struct ipv6hdr *ip6h,
- struct tcphdr *th, struct iov_tail *payload,
- uint32_t seq, bool no_tcp_csum);
+void tcp_fill_headers(const struct tcp_tap_conn *conn,
+ struct tap_hdr *taph,
+ struct iphdr *ip4h, struct ipv6hdr *ip6h,
+ struct tcphdr *th, struct iov_tail *payload,
+ const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum);
int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
bool force_seq, struct tcp_info_linux *tinfo);
diff --git a/tcp_vu.c b/tcp_vu.c
index 081c752..a611a5b 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -110,9 +110,9 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
int flags)
size_t optlen, hdrlen;
struct vu_virtq_element flags_elem[2];
struct ipv6hdr *ip6h = NULL;
+ struct iphdr *ip4h = NULL;
struct iovec flags_iov[2];
struct tcp_syn_opts *opts;
- struct iphdr *iph = NULL;
struct iov_tail payload;
struct tcphdr *th;
struct ethhdr *eh;
@@ -143,8 +143,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
int flags)
if (CONN_V4(conn)) {
eh->h_proto = htons(ETH_P_IP);
- iph = vu_ip(flags_elem[0].in_sg[0].iov_base);
- *iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
+ ip4h = vu_ip(flags_elem[0].in_sg[0].iov_base);
+ *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
th = vu_payloadv4(flags_elem[0].in_sg[0].iov_base);
} else {
@@ -170,12 +170,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn,
int flags)
flags_elem[0].in_sg[0].iov_len = hdrlen + optlen;
payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen);
- if (CONN_V4(conn)) {
- tcp_fill_headers4(conn, NULL, iph, th, &payload,
- NULL, seq, true);
- } else {
- tcp_fill_headers6(conn, NULL, ip6h, th, &payload, seq, true);
- }
+ tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
+ NULL, seq, true);
if (*c->pcap) {
tcp_vu_update_check(tapside, &flags_elem[0].in_sg[0], 1);
@@ -338,7 +334,7 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn
*conn,
struct iov_tail payload = IOV_TAIL(iov, iov_cnt, hdrlen);
char *base = iov[0].iov_base;
struct ipv6hdr *ip6h = NULL;
- struct iphdr *iph = NULL;
+ struct iphdr *ip4h = NULL;
struct tcphdr *th;
struct ethhdr *eh;
@@ -357,8 +353,8 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn
*conn,
if (!v6) {
eh->h_proto = htons(ETH_P_IP);
- iph = vu_ip(base);
- *iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
+ ip4h = vu_ip(base);
+ *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
th = vu_payloadv4(base);
} else {
eh->h_proto = htons(ETH_P_IPV6);
@@ -373,14 +369,10 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn
*conn,
th->doff = sizeof(*th) / 4;
th->ack = 1;
- if (!v6) {
- tcp_fill_headers4(conn, NULL, iph, th, &payload,
- *check, conn->seq_to_tap, true);
- *check = &iph->check;
- } else {
- tcp_fill_headers6(conn, NULL, ip6h, th, &payload,
- conn->seq_to_tap, true);
- }
+ tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
+ *check, conn->seq_to_tap, true);
+ if (ip4h)
+ *check = &ip4h->check;
}
/**
--
2.47.0