On Fri, Oct 11, 2024 at 02:35:39PM -0400, Jon Maloy wrote: > l2 tap queue entries are currently initialized at system start, and > reused with preset headers through its whole life time. The only > fields we need to update per message are things like payload size > and checksums. > > If we want to reuse these entries between ipv4 and ipv6 messages we > will need to set the pointer to the right header on the fly per > message, since the header type may differ between entries in the same > queue. > > The same needs to be done for the ethernet header. > > We do these changes here. > > Signed-off-by: Jon Maloy > > --- > v2: Setting pointers to pre-initialized IP and MAC headers instead of > copying them in on the fly. > v3: Adapted to D. Gibson's recent commit eliminitaing overlapping memcpy() > --- > tcp_buf.c | 54 ++++++++++++++++++++++++++++++------------------------ > 1 file changed, 30 insertions(+), 24 deletions(-) > > diff --git a/tcp_buf.c b/tcp_buf.c > index 238827b..e4fa59f 100644 > --- a/tcp_buf.c > +++ b/tcp_buf.c > @@ -130,8 +130,7 @@ void tcp_sock4_iov_init(const struct ctx *c) > iov = tcp4_l2_iov[i]; > > iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp4_payload_tap_hdr[i]); > - iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp4_eth_src); > - iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[i]); > + iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); > iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_payload[i]; > } > > @@ -173,8 +172,7 @@ void tcp_sock6_iov_init(const struct ctx *c) > iov = tcp6_l2_iov[i]; > > iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp6_payload_tap_hdr[i]); > - iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp6_eth_src); > - iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[i]); > + iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); > iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_payload[i]; > } > > @@ -273,11 +271,17 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) > uint32_t seq; > int ret; > > - if (CONN_V4(conn)) > - iov = tcp4_l2_flags_iov[tcp4_flags_used++]; > - else > - iov = tcp6_l2_flags_iov[tcp6_flags_used++]; > - > + if (CONN_V4(conn)) { > + iov = tcp4_l2_flags_iov[tcp4_flags_used]; > + iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_flags_ip[tcp4_flags_used]); > + iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src; > + tcp4_flags_used++; > + } else { > + iov = tcp6_l2_flags_iov[tcp6_flags_used]; > + iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_flags_ip[tcp6_flags_used]); > + iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src; > + tcp6_flags_used++; > + } > payload = iov[TCP_IOV_PAYLOAD].iov_base; > > seq = conn->seq_to_tap; > @@ -296,21 +300,19 @@ int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) > > if (flags & DUP_ACK) { > struct iovec *dup_iov; > - int i; > > if (CONN_V4(conn)) > dup_iov = tcp4_l2_flags_iov[tcp4_flags_used++]; > else > - dup_iov = tcp6_l2_flags_iov[tcp6_flags_used++]; > - > - for (i = 0; i < TCP_NUM_IOVS; i++) { > - /* All frames share the same ethernet header buffer */ > - if (i != TCP_IOV_ETH) { > - memcpy(dup_iov[i].iov_base, iov[i].iov_base, > - iov[i].iov_len); > - } > - } > - dup_iov[TCP_IOV_PAYLOAD].iov_len = iov[TCP_IOV_PAYLOAD].iov_len; > + dup_iov = tcp4_l2_flags_iov[tcp6_flags_used++]; This should be tcp6_l2_flags_iov[], no? I guess it will become when the arrays are merged in a subsequent patch. > + > + memcpy(dup_iov[TCP_IOV_TAP].iov_base, iov[TCP_IOV_TAP].iov_base, > + iov[TCP_IOV_TAP].iov_len); > + dup_iov[TCP_IOV_ETH].iov_base = iov[TCP_IOV_ETH].iov_base; > + dup_iov[TCP_IOV_IP] = IOV_OF_LVALUE(iov[TCP_IOV_IP]); This should be: dup_iov[TCP_IOV_IP] = iov[TCP_IOV_IP]; IOV_OF_LVALUE() won't work because you don't have a sized lvalue to use. In fact, I think this will make the dup packet's IP header have the contents of the struct iovec pointing at the original header, which is clearly nonsense. > + memcpy(dup_iov[TCP_IOV_PAYLOAD].iov_base, > + iov[TCP_IOV_PAYLOAD].iov_base, l4len); > + dup_iov[TCP_IOV_PAYLOAD].iov_len = l4len; > } > > if (CONN_V4(conn)) { > @@ -350,8 +352,10 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn, > } > > tcp4_frame_conns[tcp4_payload_used] = conn; > - > - iov = tcp4_l2_iov[tcp4_payload_used++]; > + iov = tcp4_l2_iov[tcp4_payload_used]; > + iov[TCP_IOV_IP] = > + IOV_OF_LVALUE(tcp4_payload_ip[tcp4_payload_used++]); > + iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src; > l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq, > false); > iov[TCP_IOV_PAYLOAD].iov_len = l4len; > @@ -359,8 +363,10 @@ static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn, > tcp_payload_flush(c); > } else if (CONN_V6(conn)) { > tcp6_frame_conns[tcp6_payload_used] = conn; > - > - iov = tcp6_l2_iov[tcp6_payload_used++]; > + iov = tcp6_l2_iov[tcp6_payload_used]; > + iov[TCP_IOV_IP] = > + IOV_OF_LVALUE(tcp6_payload_ip[tcp6_payload_used++]); > + iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src; > l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, NULL, seq, > false); > iov[TCP_IOV_PAYLOAD].iov_len = l4len; -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson