On Wed, Jul 09, 2025 at 07:47:41PM +0200, Eugenio Pérez wrote: > So vhost kernel is able to access the TCP buffers. > > Signed-off-by: Eugenio Pérez > --- > tap.c | 14 +++++++++++--- > tcp_buf.c | 14 ++++---------- > tcp_buf.h | 19 +++++++++++++++++++ > 3 files changed, 34 insertions(+), 13 deletions(-) > > diff --git a/tap.c b/tap.c > index 0656294..8b3ec45 100644 > --- a/tap.c > +++ b/tap.c > @@ -63,6 +63,8 @@ > #include "vhost_user.h" > #include "vu_common.h" > > +#include "tcp_buf.h" > + I don't love including the pretty specific content of tcp_buf.h into the mostly protocol unaware tap.c. Though I do realise that avoiding it will probably have other tradeoffs. > /* Maximum allowed frame lengths (including L2 header) */ > > /* Verify that an L2 frame length limit is large enough to contain the header, > @@ -136,8 +138,8 @@ static union { > char buf[offsetof(struct vring_used, ring[VHOST_NDESCS])]; > } vring_used_0 __attribute__((aligned(PAGE_SIZE))), vring_used_1 __attribute__((aligned(PAGE_SIZE))); > > -/* all descs ring + 2rings * 2vqs + tx pkt buf + rx pkt buf */ > -#define N_VHOST_REGIONS 6 > +/* all descs ring + 2rings * 2vqs + tx pkt buf + rx pkt buf + TCP virtio hdr + TCP eth(src,dst) + TCP ip hdr */ > +#define N_VHOST_REGIONS 12 Hmm. Keeping this and the region initialisation in sync is pretty clunky. I recall that before I went on leave we were discussing just exposing pasta's whole data segment to vhost; was there a reason for changing that plan, or just that you haven't implemented it so far? > union { > struct vhost_memory mem; > char buf[offsetof(struct vhost_memory, regions[N_VHOST_REGIONS])]; > @@ -1635,7 +1637,13 @@ static int tap_ns_tun(void *arg) > vhost_memory.mem.regions[3] = VHOST_MEMORY_REGION(vring_used_0); > vhost_memory.mem.regions[4] = VHOST_MEMORY_REGION(vring_used_1); > vhost_memory.mem.regions[5] = VHOST_MEMORY_REGION(pkt_buf); > - static_assert(5 < N_VHOST_REGIONS); > + vhost_memory.mem.regions[6] = VHOST_MEMORY_REGION(tcp_payload_tap_hdr); > + vhost_memory.mem.regions[7] = VHOST_MEMORY_REGION(tcp4_eth_src); > + vhost_memory.mem.regions[8] = VHOST_MEMORY_REGION(tcp6_eth_src); > + vhost_memory.mem.regions[9] = VHOST_MEMORY_REGION(tcp4_payload_ip); > + vhost_memory.mem.regions[10] = VHOST_MEMORY_REGION(tcp6_payload_ip); > + vhost_memory.mem.regions[11] = VHOST_MEMORY_REGION(tcp_payload); > + static_assert(11 < N_VHOST_REGIONS); If all the regions are global variables, you could put them into a static const array, then define N_VHOST_REGIONS via ARRAY_SIZE(). > #undef VHOST_MEMORY_REGION > #undef VHOST_MEMORY_REGION_PTR > > diff --git a/tcp_buf.c b/tcp_buf.c > index 2fbd056..c999d2e 100644 > --- a/tcp_buf.c > +++ b/tcp_buf.c > @@ -22,8 +22,6 @@ > > #include > > -#include > - > #include "util.h" > #include "ip.h" > #include "iov.h" > @@ -35,24 +33,20 @@ > #include "tcp_internal.h" > #include "tcp_buf.h" > > -#define TCP_FRAMES_MEM 128 > -#define TCP_FRAMES \ > - (c->mode == MODE_PASTA ? 1 : TCP_FRAMES_MEM) > - > /* Static buffers */ > > /* Ethernet header for IPv4 and IPv6 frames */ > -static struct ethhdr tcp4_eth_src; > -static struct ethhdr tcp6_eth_src; > +struct ethhdr tcp4_eth_src; > +struct ethhdr tcp6_eth_src; > > -static struct virtio_net_hdr_mrg_rxbuf tcp_payload_tap_hdr[TCP_FRAMES_MEM]; > +struct virtio_net_hdr_mrg_rxbuf tcp_payload_tap_hdr[TCP_FRAMES_MEM]; > > /* IP headers for IPv4 and IPv6 */ > struct iphdr tcp4_payload_ip[TCP_FRAMES_MEM]; > struct ipv6hdr tcp6_payload_ip[TCP_FRAMES_MEM]; > > /* TCP segments with payload for IPv4 and IPv6 frames */ > -static struct tcp_payload_t tcp_payload[TCP_FRAMES_MEM]; > +struct tcp_payload_t tcp_payload[TCP_FRAMES_MEM]; > > static_assert(MSS4 <= sizeof(tcp_payload[0].data), "MSS4 is greater than 65516"); > static_assert(MSS6 <= sizeof(tcp_payload[0].data), "MSS6 is greater than 65516"); > diff --git a/tcp_buf.h b/tcp_buf.h > index 54f5e53..7ae2536 100644 > --- a/tcp_buf.h > +++ b/tcp_buf.h > @@ -6,9 +6,28 @@ > #ifndef TCP_BUF_H > #define TCP_BUF_H > > +#include > + > +#include "tcp_conn.h" > +#include "tcp_internal.h" > + > void tcp_sock_iov_init(const struct ctx *c); > void tcp_payload_flush(const struct ctx *c); > +struct tcp_tap_conn; > int tcp_buf_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn); > int tcp_buf_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags); > > +#define TCP_FRAMES_MEM 128 > +#define TCP_FRAMES \ > +(c->mode == MODE_PASTA ? 1 : TCP_FRAMES_MEM) > + > +extern struct virtio_net_hdr_mrg_rxbuf tcp_payload_tap_hdr[TCP_FRAMES_MEM]; > +extern struct tcp_payload_t tcp_payload[TCP_FRAMES_MEM]; > + > +extern struct ethhdr tcp4_eth_src; > +extern struct ethhdr tcp6_eth_src; > + > +extern struct iphdr tcp4_payload_ip[TCP_FRAMES_MEM]; > +extern struct ipv6hdr tcp6_payload_ip[TCP_FRAMES_MEM]; > + > #endif /*TCP_BUF_H */ -- 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