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([2a01:e0a:e10:ef90:8e19:3414:44f0:befd]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36075093a13sm1696340f8f.9.2024.06.13.05.58.42 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 13 Jun 2024 05:58:42 -0700 (PDT) Message-ID: <8d038a70-76fe-4aab-ab6f-81ffa63ff797@redhat.com> Date: Thu, 13 Jun 2024 14:58:42 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 1/8] tcp: extract buffer management from tcp_send_flag() To: passt-dev@passt.top References: <20240613123655.1362065-1-lvivier@redhat.com> <20240613123655.1362065-2-lvivier@redhat.com> From: Laurent Vivier Autocrypt: addr=lvivier@redhat.com; keydata= xsFNBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABzSNMYXVyZW50IFZp dmllciA8bHZpdmllckByZWRoYXQuY29tPsLBeAQTAQIAIgUCVgVQgAIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjwpgg//fSGy0Rs/t8cPFuzoY1cex4limJQfReLr SJXCANg9NOWy/bFK5wunj+h/RCFxIFhZcyXveurkBwYikDPUrBoBRoOJY/BHK0iZo7/WQkur 6H5losVZtrotmKOGnP/lJYZ3H6OWvXzdz8LL5hb3TvGOP68K8Bn8UsIaZJoeiKhaNR0sOJyI YYbgFQPWMHfVwHD/U+/gqRhD7apVysxv5by/pKDln1I5v0cRRH6hd8M8oXgKhF2+rAOL7gvh jEHSSWKUlMjC7YwwjSZmUkL+TQyE18e2XBk85X8Da3FznrLiHZFHQ/NzETYxRjnOzD7/kOVy gKD/o7asyWQVU65mh/ECrtjfhtCBSYmIIVkopoLaVJ/kEbVJQegT2P6NgERC/31kmTF69vn8 uQyW11Hk8tyubicByL3/XVBrq4jZdJW3cePNJbTNaT0d/bjMg5zCWHbMErUib2Nellnbg6bc 2HLDe0NLVPuRZhHUHM9hO/JNnHfvgiRQDh6loNOUnm9Iw2YiVgZNnT4soUehMZ7au8PwSl4I KYE4ulJ8RRiydN7fES3IZWmOPlyskp1QMQBD/w16o+lEtY6HSFEzsK3o0vuBRBVp2WKnssVH qeeV01ZHw0bvWKjxVNOksP98eJfWLfV9l9e7s6TaAeySKRRubtJ+21PRuYAxKsaueBfUE7ZT 7zfOwU0EVgUmGQEQALxSQRbl/QOnmssVDxWhHM5TGxl7oLNJms2zmBpcmlrIsn8nNz0rRyxT 460k2niaTwowSRK8KWVDeAW6ZAaWiYjLlTunoKwvF8vP3JyWpBz0diTxL5o+xpvy/Q6YU3BN efdq8Vy3rFsxgW7mMSrI/CxJ667y8ot5DVugeS2NyHfmZlPGE0Nsy7hlebS4liisXOrN3jFz asKyUws3VXek4V65lHwB23BVzsnFMn/bw/rPliqXGcwl8CoJu8dSyrCcd1Ibs0/Inq9S9+t0 VmWiQWfQkz4rvEeTQkp/VfgZ6z98JRW7S6l6eophoWs0/ZyRfOm+QVSqRfFZdxdP2PlGeIFM C3fXJgygXJkFPyWkVElr76JTbtSHsGWbt6xUlYHKXWo+xf9WgtLeby3cfSkEchACrxDrQpj+ Jt/JFP+q997dybkyZ5IoHWuPkn7uZGBrKIHmBunTco1+cKSuRiSCYpBIXZMHCzPgVDjk4viP brV9NwRkmaOxVvye0vctJeWvJ6KA7NoAURplIGCqkCRwg0MmLrfoZnK/gRqVJ/f6adhU1oo6 z4p2/z3PemA0C0ANatgHgBb90cd16AUxpdEQmOCmdNnNJF/3Zt3inzF+NFzHoM5Vwq6rc1JP jfC3oqRLJzqAEHBDjQFlqNR3IFCIAo4SYQRBdAHBCzkM4rWyRhuVABEBAAHCwV8EGAECAAkF AlYFJhkCGwwACgkQ8ww4vT8vvjwg9w//VQrcnVg3TsjEybxDEUBm8dBmnKqcnTBFmxN5FFtI WlEuY8+YMiWRykd8Ln9RJ/98/ghABHz9TN8TRo2b6WimV64FmlVn17Ri6FgFU3xNt9TTEChq AcNg88eYryKsYpFwegGpwUlaUaaGh1m9OrTzcQy+klVfZWaVJ9Nw0keoGRGb8j4XjVpL8+2x OhXKrM1fzzb8JtAuSbuzZSQPDwQEI5CKKxp7zf76J21YeRrEW4WDznPyVcDTa+tz++q2S/Bp P4W98bXCBIuQgs2m+OflERv5c3Ojldp04/S4NEjXEYRWdiCxN7ca5iPml5gLtuvhJMSy36gl U6IW9kn30IWuSoBpTkgV7rLUEhh9Ms82VWW/h2TxL8enfx40PrfbDtWwqRID3WY8jLrjKfTd R3LW8BnUDNkG+c4FzvvGUs8AvuqxxyHbXAfDx9o/jXfPHVRmJVhSmd+hC3mcQ+4iX5bBPBPM oDqSoLt5w9GoQQ6gDVP2ZjTWqwSRMLzNr37rJjZ1pt0DCMMTbiYIUcrhX8eveCJtY7NGWNyx FCRkhxRuGcpwPmRVDwOl39MB3iTsRighiMnijkbLXiKoJ5CDVvX5yicNqYJPKh5MFXN1bvsB kmYiStMRbrD0HoY1kx5/VozBtc70OU0EB8Wrv9hZD+Ofp0T3KOr1RUHvCZoLURfFhSQ= In-Reply-To: <20240613123655.1362065-2-lvivier@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: 6MIRUMO7QECGOQOTGCNW7XYR5UNMUP7J X-Message-ID-Hash: 6MIRUMO7QECGOQOTGCNW7XYR5UNMUP7J X-MailFrom: lvivier@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 13/06/2024 14:36, Laurent Vivier wrote: > This commit isolates the internal data structure management used for storing > data (e.g., tcp4_l2_flags_iov[], tcp6_l2_flags_iov[], tcp4_flags_ip[], > tcp4_flags[], ...) from the tcp_send_flag() function. The extracted > functionality is relocated to a new function named tcp_fill_flag_header(). > > tcp_fill_flag_header() is now a generic function that accepts parameters such > as struct tcphdr and a data pointer. tcp_send_flag() utilizes this parameter to > pass memory pointers from tcp4_l2_flags_iov[] and tcp6_l2_flags_iov[]. > > This separation sets the stage for utilizing tcp_fill_flag_header() to > set the memory provided by the guest via vhost-user in future developments. Forgot to update the comment: s/tcp_fill_flag_header/tcp_prepare_flags/ Could you update on merge? Thanks, Laurent > Signed-off-by: Laurent Vivier > --- > tcp.c | 78 +++++++++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 54 insertions(+), 24 deletions(-) > > diff --git a/tcp.c b/tcp.c > index dd8d46e08628..e40f42259451 100644 > --- a/tcp.c > +++ b/tcp.c > @@ -1567,24 +1567,25 @@ static void tcp_update_seqack_from_tap(const struct ctx *c, > } > > /** > - * tcp_send_flag() - Send segment with flags to tap (no payload) > + * tcp_prepare_flags() - Prepare header for flags-only segment (no payload) > * @c: Execution context > * @conn: Connection pointer > * @flags: TCP flags: if not set, send segment only if ACK is due > + * @th: TCP header to update > + * @data: buffer to store TCP option > + * @optlen: size of the TCP option buffer (output parameter) > * > - * Return: negative error code on connection reset, 0 otherwise > + * Return: < 0 error code on connection reset, > + * 0 if there is no flag to send > + * 1 otherwise > */ > -static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) > +static int tcp_prepare_flags(struct ctx *c, struct tcp_tap_conn *conn, > + int flags, struct tcphdr *th, char *data, > + size_t *optlen) > { > - struct tcp_flags_t *payload; > struct tcp_info tinfo = { 0 }; > socklen_t sl = sizeof(tinfo); > int s = conn->sock; > - size_t optlen = 0; > - struct tcphdr *th; > - struct iovec *iov; > - size_t l4len; > - char *data; > > if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap) && > !flags && conn->wnd_to_tap) > @@ -1606,20 +1607,12 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) > if (!tcp_update_seqack_wnd(c, conn, flags, &tinfo) && !flags) > return 0; > > - if (CONN_V4(conn)) > - iov = tcp4_l2_flags_iov[tcp4_flags_used++]; > - else > - iov = tcp6_l2_flags_iov[tcp6_flags_used++]; > - > - payload = iov[TCP_IOV_PAYLOAD].iov_base; > - th = &payload->th; > - data = payload->opts; > - > + *optlen = 0; > if (flags & SYN) { > int mss; > > /* Options: MSS, NOP and window scale (8 bytes) */ > - optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN; > + *optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN; > > *data++ = OPT_MSS; > *data++ = OPT_MSS_LEN; > @@ -1653,17 +1646,13 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) > flags |= ACK; > } > > - th->doff = (sizeof(*th) + optlen) / 4; > + th->doff = (sizeof(*th) + *optlen) / 4; > > th->ack = !!(flags & ACK); > th->rst = !!(flags & RST); > th->syn = !!(flags & SYN); > th->fin = !!(flags & FIN); > > - l4len = tcp_l2_buf_fill_headers(c, conn, iov, optlen, NULL, > - conn->seq_to_tap); > - iov[TCP_IOV_PAYLOAD].iov_len = l4len; > - > if (th->ack) { > if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap)) > conn_flag(c, conn, ~ACK_TO_TAP_DUE); > @@ -1678,6 +1667,47 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) > if (th->fin || th->syn) > conn->seq_to_tap++; > > + return 1; > +} > + > +/** > + * tcp_send_flag() - Send segment with flags to tap (no payload) > + * @c: Execution context > + * @conn: Connection pointer > + * @flags: TCP flags: if not set, send segment only if ACK is due > + * > + * Return: negative error code on connection reset, 0 otherwise > + */ > +static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) > +{ > + struct tcp_flags_t *payload; > + struct iovec *iov; > + size_t optlen; > + size_t l4len; > + 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++]; > + > + payload = iov[TCP_IOV_PAYLOAD].iov_base; > + > + seq = conn->seq_to_tap; > + ret = tcp_prepare_flags(c, conn, flags, &payload->th, > + payload->opts, &optlen); > + if (ret <= 0) { > + if (CONN_V4(conn)) > + tcp4_flags_used--; > + else > + tcp6_flags_used--; > + return ret; > + } > + > + l4len = tcp_l2_buf_fill_headers(c, conn, iov, optlen, NULL, seq); > + iov[TCP_IOV_PAYLOAD].iov_len = l4len; > + > if (flags & DUP_ACK) { > struct iovec *dup_iov; > int i;