target/linux/bcm27xx/patches-6.1/950-0821-can-isotp-add-module-parameter-for-maximum-pdu-size.patch

   1 From 4b729a06b15fc5ee3694dcc62346dcb718ae4290 Mon Sep 17 00:00:00 2001
   2 From: Oliver Hartkopp <socketcan@hartkopp.net>
   3 Date: Sun, 26 Mar 2023 13:59:11 +0200
   4 Subject: [PATCH] can: isotp: add module parameter for maximum pdu size
   5
   6 commit 96d1c81e6a0478535342dff6c730adb076cd84e8 upstream.
   7
   8 With ISO 15765-2:2016 the PDU size is not limited to 2^12 - 1 (4095)
   9 bytes but can be represented as a 32 bit unsigned integer value which
  10 allows 2^32 - 1 bytes (~4GB). The use-cases like automotive unified
  11 diagnostic services (UDS) and flashing of ECUs still use the small
  12 static buffers which are provided at socket creation time.
  13
  14 When a use-case requires to transfer PDUs up to 1025 kByte the maximum
  15 PDU size can now be extended by setting the module parameter
  16 max_pdu_size. The extended size buffers are only allocated on a
  17 per-socket/connection base when needed at run-time.
  18
  19 changes since v2: https://lore.kernel.org/all/20230313172510.3851-1-socketcan@hartkopp.net
  20 - use ARRAY_SIZE() to reference DEFAULT_MAX_PDU_SIZE only at one place
  21
  22 changes since v1: https://lore.kernel.org/all/20230311143446.3183-1-socketcan@hartkopp.net
  23 - limit the minimum 'max_pdu_size' to 4095 to maintain the classic
  24   behavior before ISO 15765-2:2016
  25
  26 Link: https://github.com/raspberrypi/linux/issues/5371
  27 Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
  28 Link: https://lore.kernel.org/all/20230326115911.15094-1-socketcan@hartkopp.net
  29 Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
  30 ---
  31  net/can/isotp.c | 65 ++++++++++++++++++++++++++++++++++++++++++-------
  32  1 file changed, 56 insertions(+), 9 deletions(-)
  33
  34 --- a/net/can/isotp.c
  35 +++ b/net/can/isotp.c
  36 @@ -85,10 +85,21 @@ MODULE_ALIAS("can-proto-6");
  37
  38  /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
  39   * take full 32 bit values (4 Gbyte). We would need some good concept to handle
  40 - * this between user space and kernel space. For now increase the static buffer
  41 - * to something about 64 kbyte to be able to test this new functionality.
  42 + * this between user space and kernel space. For now set the static buffer to
  43 + * something about 8 kbyte to be able to test this new functionality.
  44   */
  45 -#define MAX_MSG_LENGTH 66000
  46 +#define DEFAULT_MAX_PDU_SIZE 8300
  47 +
  48 +/* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
  49 +#define MAX_12BIT_PDU_SIZE 4095
  50 +
  51 +/* limit the isotp pdu size from the optional module parameter to 1MByte */
  52 +#define MAX_PDU_SIZE (1025 * 1024U)
  53 +
  54 +static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
  55 +module_param(max_pdu_size, uint, 0444);
  56 +MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
  57 +                __stringify(DEFAULT_MAX_PDU_SIZE) ")");
  58
  59  /* N_PCI type values in bits 7-4 of N_PCI bytes */
  60  #define N_PCI_SF 0x00  /* single frame */
  61 @@ -124,13 +135,15 @@ enum {
  62  };
  63
  64  struct tpcon {
  65 -       unsigned int idx;
  66 +       u8 *buf;
  67 +       unsigned int buflen;
  68         unsigned int len;
  69 +       unsigned int idx;
  70         u32 state;
  71         u8 bs;
  72         u8 sn;
  73         u8 ll_dl;
  74 -       u8 buf[MAX_MSG_LENGTH + 1];
  75 +       u8 sbuf[DEFAULT_MAX_PDU_SIZE];
  76  };
  77
  78  struct isotp_sock {
  79 @@ -498,7 +511,17 @@ static int isotp_rcv_ff(struct sock *sk,
  80         if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
  81                 return 1;
  82
  83 -       if (so->rx.len > MAX_MSG_LENGTH) {
  84 +       /* PDU size > default => try max_pdu_size */
  85 +       if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
  86 +               u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
  87 +
  88 +               if (newbuf) {
  89 +                       so->rx.buf = newbuf;
  90 +                       so->rx.buflen = max_pdu_size;
  91 +               }
  92 +       }
  93 +
  94 +       if (so->rx.len > so->rx.buflen) {
  95                 /* send FC frame with overflow status */
  96                 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
  97                 return 1;
  98 @@ -802,7 +825,7 @@ static void isotp_create_fframe(struct c
  99                 cf->data[0] = so->opt.ext_address;
 100
 101         /* create N_PCI bytes with 12/32 bit FF_DL data length */
 102 -       if (so->tx.len > 4095) {
 103 +       if (so->tx.len > MAX_12BIT_PDU_SIZE) {
 104                 /* use 32 bit FF_DL notation */
 105                 cf->data[ae] = N_PCI_FF;
 106                 cf->data[ae + 1] = 0;
 107 @@ -939,7 +962,17 @@ static int isotp_sendmsg(struct socket *
 108                         goto err_event_drop;
 109         }
 110
 111 -       if (!size || size > MAX_MSG_LENGTH) {
 112 +       /* PDU size > default => try max_pdu_size */
 113 +       if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
 114 +               u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
 115 +
 116 +               if (newbuf) {
 117 +                       so->tx.buf = newbuf;
 118 +                       so->tx.buflen = max_pdu_size;
 119 +               }
 120 +       }
 121 +
 122 +       if (!size || size > so->tx.buflen) {
 123                 err = -EINVAL;
 124                 goto err_out_drop;
 125         }
 126 @@ -1194,6 +1227,12 @@ static int isotp_release(struct socket *
 127         so->ifindex = 0;
 128         so->bound = 0;
 129
 130 +       if (so->rx.buf != so->rx.sbuf)
 131 +               kfree(so->rx.buf);
 132 +
 133 +       if (so->tx.buf != so->tx.sbuf)
 134 +               kfree(so->tx.buf);
 135 +
 136         sock_orphan(sk);
 137         sock->sk = NULL;
 138
 139 @@ -1588,6 +1627,11 @@ static int isotp_init(struct sock *sk)
 140         so->rx.state = ISOTP_IDLE;
 141         so->tx.state = ISOTP_IDLE;
 142
 143 +       so->rx.buf = so->rx.sbuf;
 144 +       so->tx.buf = so->tx.sbuf;
 145 +       so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
 146 +       so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
 147 +
 148         hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
 149         so->rxtimer.function = isotp_rx_timer_handler;
 150         hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
 151 @@ -1670,7 +1714,10 @@ static __init int isotp_module_init(void
 152  {
 153         int err;
 154
 155 -       pr_info("can: isotp protocol\n");
 156 +       max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
 157 +       max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
 158 +
 159 +       pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
 160
 161         err = can_proto_register(&isotp_can_proto);
 162         if (err < 0)